A slate of Democratic presidential candidates will this weekend speak at South by Southwest (SXSW), seeking to connect with a young and liberal crowd at the tech-heavy festival in Austin.

Among declared candidates for the party nomination, Senator Amy Klobuchar of Minnesota was the first to take the stage on Saturday, followed by Senator Elizabeth Warren of Massachusetts later in the afternoon.

The former San Antonio mayor Julian Castro, the former Colorado governor John Hickenlooper and Washington’s governor, Jay Inslee, will speak on Sunday.

Klobuchar, who has been dogged by reports of mistreating her staff, was asked about the allegations and repeated a defense she used last month at a rally.

“I have high expectations for myself and I have high expectations for the people who work for me and I have high expectations for this country,” she said.

Klobuchar said she was “sometimes too tough” on the people who worked for her, then moved on to questions about the crowded Democratic field and tech policy.

She said she wanted to investigate how tech firms such as Facebook and Google have monopolized power and obtained vast amounts of user data.

“The first thing we do is privacy legislation,” Klobuchar said. “Second thing we do is look at how much they’re making off of us.”

Hours later, Warren faced an audience that included employees of Amazon, Facebook and Google and explained the pledge she made on Friday to rein in the influence such big-tech companies have on American lives.

Warren said a problem had emerged in the tech industry where companies such as Amazon have data on buyers and sellers and are able to compete in online markets in a different way from average sellers and small businesses.

“My view on this is: it’s a little like baseball,” Warren said. “You can be an umpire, a platform, or you can own teams, that’s fine. But you can’t be an umpire and own teams.”

In a quick-fire round of questions, Warren said she thought hype directed at the New York representative Alexandria Ocasio-Cortez, who was to speak later Saturday evening at SXSW, was justified.

She also said she read two books per week, mostly by listening to audiobooks, and confessed that her drink of choice was the beer Michelob Ultra, “the club soda of beers”.

Three underdog candidates are also scheduled to speak at the festival, at a CNN-hosted town hall on Sunday night. They are the former Maryland congressman John Delaney; the South Bend, Indiana, mayor Pete Buttigieg; and the Hawaii congresswoman Tulsi Gabbard.

The California senator Kamala Harris, a heavyweight contender, will not appear. On Saturday, she was due to appear in South Carolina. Hickenlooper and the Vermont senator Bernie Sanders were visiting Iowa.

In Austin on Saturday, the former Texas congressman Beto O’Rourke attended the premiere of a documentary chronicling his long-shot US Senate campaign that ended in a narrow defeat by the hardline Republican incumbent, Ted Cruz. O’Rourke has not yet announced if he will run for president.

The film, Running with Beto, will air on HBO and was cobbled together from 700 hours of campaign footage. After its premiere, O’Rourke, who attended with his wife and daughter, said he had made up his mind about whether to run or not and plans to let everyone know soon.

O’Rourke briefly took questions from reporters but provided no details. Seeing the documentary was “very emotional”, he said.