The high-stakes meeting between Biden and Putin comes on the heels of a summit with NATO leaders in Belgium's capital, another first for Biden as U.S. president.

"What I'll convey to President Putin is that I'm not looking for conflict with Russia but that we will respond if Russia continues its harmful activities," Biden said at a press conference in Brussels. "And we will not fail to defend the trans-Atlantic alliance or stand up for democratic values."

Biden said not a single NATO leader expressed reservations about him meeting with Putin but rather have "thanked" him for doing it.

"I had discussions with them about -- in the open -- about what they thought was important from their perspective and what they thought was not important," he said.

Biden and Putin's meeting is slated to begin on Wednesday around 7 a.m. ET and last four to five hours total, with multiple sessions.

The two leaders will first take part in a small session, joined by U.S. Secretary of State Antony Blinken and Russian Foreign Minister Sergey Lavrov, before taking part in a larger working session.

The two leaders are also expected to host dueling, solo press conferences following the summit.

Biden said they weren't holding a joint news conference, as Trump did with Putin, because he didn't want the focus to be on talking time or body language. Doing it this way leaves Putin with less of an opportunity to embarrass the American president, as he's historically tried to do.

"I think the best way to deal with this is for he and I to meet, he and I to have our discussion," Biden said Sunday in England, on another leg of his first trip as president. "I don't want to get into being diverted by, did they shake hands, who talked the most and the rest."

While he is no stranger to Putin, Biden has been intensely prepping for the meeting, receiving at least once-a-day briefings for weeks leading up to the summit.

"He's been preparing for this like he prepares for every significant international engagement. He reviews the issues -- written material; he cares about digging into the details. That very much matters to him," a senior administration official said Tuesday.

The White House has also called on experts to help Biden prep for the meeting -- including Fiona Hill, a top Russia expert and National Security and former Trump administration official who famously said she considered faking a medical emergency to end Trump’s press conference with Putin in 2018 in Helsinki, Finland.

Wednesday's meeting is slated to last four to five hours total, with multiple sessions.

-ABC News' Molly Nagle

Biden arrived in Geneva earlier Tuesday less than 24 hours ahead of his meeting with Putin, scheduled for Wednesday around 7 a.m. ET and expected to last several hours.

Looking to project confidence ahead of the high-stakes summit, Biden didn’t miss a beat during a photo op Tuesday with Swiss President Guy Parmelin.

"Mr. President, are you ready for tomorrow?" a reporter asked.

"I’m always ready," Biden replied.

The meeting with the Swiss president was Biden's final public event for the day.

When the president arrived earlier in Geneva, he was met with a long line of greeters, many dressed in colorful outfits, as he stepped off Air Force One.

The White House said Biden will hold a solo press conference after meeting with Putin, where he will give his takeaways. Putin plans to do the same.

Biden and Putin's first -- and likely only -- photo op inside their summit was met with a chaotic scene.

According to a pool report, the chaos began outside the room with "10 minutes of a shoving match" between the U.S. and Russian security, press and delegations, with each side aiming to get inside. American reporters were first to go in but not all were let inside.

Already seated, Biden nodded while they shouted questions, including whether the two leaders can trust each other -- but the White House is already disputing that Biden was nodding yes to that.

"It was a chaotic scrum with reporters shouting over each other. @POTUS was very clearly not responding to any one question, but nodding in acknowledgment to the press generally. He said just two days ago in his presser: 'verify, then trust," White House communications director Kate Bedingfield said in a tweet.

Another reporter asked Putin if he feared imprisoned Russian opposition leader Aleksei Navalny and what he would do if Ukraine is allowed to join NATO. Putin didn't answer.

On the way out, another shoving match ensued.

"Lots of shoving and grabbing - it was extremely aggressive," one American pool reporter said. "The Russian security pulled on our clothes and shoved us as we tried to stay in the room. They eventually pushed us out the door."