In rally after rally, and speech upon speech, Donald Trump built a verbal skyscraper of campaign promises about what he would do on his first day in the White House.

Begin building a wall at the nation's southern border. End the "war on coal." Label China a currency manipulator. The list went on and on.

But now, as Trump prepares to take the oath of office Friday, his Day One executive actions and policy plans are a closely held secret, another prop in the Donald Trump show waiting to be unveiled with his trademark flourish and fanfare. And, his aides are playing down how much will be done during that first day, while also sending conflicting signals about whether the real work of governing will begin Friday, when Trump officially becomes president, or Monday, his first full workday in the White House.

Incoming White House press secretary Sean Spicer said Trump will probably sign four or five executive actions on Friday, mainly focused on logistics and government operations, with more coming Monday.

Asked Thursday about Trump's coming executive actions, Spicer declined to give specifics, but he mentioned Obama's health-care law, the fight against the Islamic State and immigration as "key issues" important to Trump.

"He is committed to not just Day One, but Day Two, Day Three, of enacting an agenda of real change," he told reporters. "And I think that you're gonna see that in the days and weeks to come."

Regardless of what happens on Day One, advisers to the president-elect and others close to the transition process say Trump will act quickly in the early days of his administration. His initial plans are to undo many of President Barack Obama's executive actions and begin rolling back regulations, especially those he believes are financially burdensome. At least to start, the advisers said, he will focus more on unraveling the past eight years of the outgoing administration than on launching a new Trump vision.

Several advisers used the word "aggressive" to describe Trump's early actions, with another predicting "a tsunami." The plans are still being drafted and tweaked, in a last-minute effort that spans the transition team, including the legal department, policy shop, legislative team and communications operation. The effort is being spearheaded by Stephen Miller, Trump's senior policy adviser.

One said to expect actions undoing aspects of Obama's health-care policy in the first wave of signings and added that Trump will probably reinstate the "Mexico City" policy, first implemented under President Ronald Reagan, that basically prevents groups receiving U.S. foreign aid from performing or promoting abortion services as a family-planning method.

Trump's promises both on the campaign trail and since the election have set high expectations among his supporters for what he will do in the first days and weeks of his presidency. A failure to deliver likely will be seen as a setback for the new administration.

Rep. Chris Collins, R-N.Y., a member of Trump's transition team, said that when Vice President-elect Mike Pence met with congressional Republicans earlier this month, he offered them a simple message: "That President-elect Trump is going to walk down Pennsylvania Avenue in the parade and go into the Oval Office with a stack of papers on the desk and start signing them to roll back what we call Obama's unconstitutional executive actions."

Trump aides have yet to clarify, however, how many of his first moves will be actual executive actions that will take effect immediately and how many will be grand proclamations that may take time to fully implement.

Senate leaders, meanwhile, hope to confirm several of his Cabinet nominees as early as Friday, especially those filling national security posts, including retired Gen. John Kelly to lead the Department of Homeland Security and retired Gen. James Mattis as secretary of defense. Rep. Mike Pompeo, R-Kan., Trump's pick head the CIA, could get his vote on Monday.

A speech Trump delivered in October in Gettysburg, Pennsylvania – at the time intended to be his closing argument to voters – will serve as a blueprint for his initial policy prescriptions, according to his aides. There, in the shadow of the Civil War battlefield, Trump promised on his first day in office more than a dozen actions, ranging from the less likely – proposing a constitutional amendment imposing term limits on members of Congress – to the more plausible- withdrawing from and beginning to renegotiate key trade deals.

After the initial rush, the contours of Trump's first 100 days in office offer more of a combination of both undoing some of the Obama administration's policies and implementing his own legislative vision. His priorities, said a senior Trump adviser, include an infrastructure plan; cracking down on what he views as trade abuses; building a wall at the nation's southern border and tackling visa overstays; expanding production of domestic energy sources; a new tax plan that includes a child-care tax credit; and family leave proposals.

Congressional Republicans are already planning to use a fast-track budget process to begin repealing Obama's health-care plan. And Senate Republicans say a second budget of the year, in April, could give the new administration additional tools – through the same process – to muscle through its tax plan.

Stephen Moore, an economist for the Heritage Foundation who served as a senior adviser to the campaign, said that over the summer, once it became clear that Trump would be the Republican nominee, he began helping with what he called the "First Day Project" – a set of actions that Trump could take on his first day in office to begin rolling back the previous administration's policies.

"The idea has always been to get Trump ready with a pen that he can use his first day in the Oval Office to start overturning executive actions and executive orders that Obama has signed into law over the last four or five years," Moore said. "If a president signs an executive order, a new president can come in and with the stroke of a pen rescind that order."

Moore said one area of acute focus was Obama's energy and environment regulations, including his 2015 Clean Power Plan to curb carbon pollution from power plants.

"There's such an ideological night and day comparison between Obama and Trump, that if we want to be successful, we need to undo everything Obama did," he added. "That's a bit of an exaggeration, but there's very few things Obama has done that we regard as being helpful to the economy."

The Trump campaign also had outside help in formulating its early executive actions, though it remains unclear just how much of the unsolicited advice the Trump operation has accepted or plans to implement.

In early 2015, for instance, well before a Republican nominee had emerged, Crossroads GPS, the nonprofit arm of the Karl Rove's American Crossroads, began compiling a document outlining a comprehensive list of executive actions an incoming Republican president could take to facilitate economic growth. The document spanned dozens of pages and multiple policy areas, with two to three lawyers assigned to each topic, and was passed to several Republican campaigns, including Trump's.

In a May 2016 memo, Bernie Marcus, co-founder of Home Depot, also outlined his plans to financially support the Crossroads project. Michael Caputo, then a Trump adviser who was also a longtime adviser to Marcus, drafted the memo and passed it along to Trump.

"One option many presidents overlook is to make early, effective use of constitutional executive powers – through executive orders, enforcement directives, rule-makings and other actions that do not require congressional or budget approval to effectuate," reads the one-page memo. "The unifying goal of these various executive actions is to jump start the economy and create jobs."

Caputo confirmed that he wrote the memo and presented it to Trump, but he declined to comment further. A spokeswoman for Marcus said she was unaware of the memo, and a spokesman for Crossroads also declined to comment.

A May 2016 draft of the energy and environmental portion of the document calls on rolling back the Environmental Protection Agency's Clean Power Plan through executive order, and it also lists withdrawing from the Paris Climate Accord as a "high" priority for the first 100 days. Since winning election, Trump has sent mixed signals on the international climate agreement.

Of course, the Trump operation is hardly the first to prepare a robust list of executive actions for an incoming president. Mitt Romney's transition team, which began work well before Election Day in 2012, combed through all of Romney's policy speeches and op-eds, identifying and prioritizing all the promises he had made during the campaign, and drafted a 200-day plan.

On the list: Everything from repealing and replacing Obama's signature health-care law to using state police to help arrest undocumented immigrants for deportation, said someone familiar with the plans.

Former Utah governor Mike Leavitt, who headed Romney's transition team, said if Romney had won, his transition aides had begun planning for various scenarios, because they weren't sure which chambers of Congress, if any, they would control. With Republicans now controlling the House and the Senate, the Trump administration, he added, should theoretically be able to take bold and decisive action.

"They have the benefit of having control of both houses of Congress," Leavitt said, "so probably a lot more will be accomplished than if they had a divided government."