WASHINGTON — After a marathon debate about how to conduct the impeachment trial, the Senate will formally move into the oral arguments phase of the proceeding on Wednesday as the House managers open their case to convict President Trump and remove him from office.

The managers will present their two articles of impeachment charging Mr. Trump with abuse of power and obstruction of Congress as they begin what will be as much as 24 hours of opening arguments over three days. With no guarantee of being able to call witnesses later, these three days may be the main opportunity for the prosecution.

The basics.

What we’re expecting to see: Each of the seven House managers, led by Representative Adam B. Schiff, Democrat of California, will present different elements of the case in a series of speeches. They will have a chance to make their points without being challenged by either senators or the White House lawyers, who will get their opportunity to make arguments later.

When we’re likely to see it: The trial convenes at 1 p.m. Eastern and will last through the afternoon and into the evening. If the managers divide their total of 24 allotted hours evenly over three days, the arguments could go until 9 p.m. or later depending on breaks. The White House could pre-empt the arguments with a motion to dismiss on Wednesday morning, but allies said it was unlikely to do so because it does not have enough votes.