The People of the State of New York v. Donald J. Trump, et al, is scheduled to get underway in lower Manhattan at 10 a.m. with opening statements.

If opening statements are completed before the end of the day, the New York attorney general plans to begin her case by calling Trump's former Mazars USA accountant Donald Bender to the stand.

Mazars severed its business relationship with the former president last year after learning of the attorney general's findings during the AG's probe.

Though Trump has denied all wrongdoing alleged by the attorney general, Judge Arthur Engoron has already decided the central allegation against Trump and his co-defendants, ruling in a pretrial hearing last week that the AG had provided "conclusive evidence" that Trump overvalued his assets between $812 million and $2.2 billion.

The judge then canceled the Trump Organization's business certificates in New York, severely restricting Trump's ability to conduct business in the state moving forward -- a move that Trump attorney Alina Habba called "nonsensical" and "outrageously overreaching."

"In defendants' world: rent regulated apartments are worth the same as unregulated apartments; restricted land is worth the same as unrestricted land; restrictions can evaporate into thin air," Engoron wrote, citing multiple arguments made by defense to justify the allegedly inflated valuations of Trump's assets. "That is a fantasy world, not the real world."

Among the issues still to be determined at trial: What additional penalties Trump might face, and what might happen with the multiple causes of action included in the attorney general's suit.

Former President Donald Trump stepped up his attacks on the judge overseeing and deciding his case, writing on Truth Social overnight that Justice Arthur Engoron should resign and be sanctioned for "abuse of power."

Similar to an earlier post, Trump criticized allegations regarding the value of his Mar-a-Lago estate, in addition to an appellate court's ruling that his lawyers unsuccessfully tried to use to limit the timeframe of the case.

Former President Trump posted on his Truth Social platform Sunday night that he intends to attend the opening of the trial.

"See you in court -- Monday morning," he wrote in a post.

Earlier Sunday, multiple sources familiar with the decision told ABC News that Trump was expecting to attend.

Trump will have no speaking role in court on Monday, but it is anticipated that he'll return to the courthouse toward the end of the state's case when court records show he will be called as a witness.

Donald Trump acknowledged during direct examination that he overvalued at least two properties in his statements of financial condition, though he broadly represented that the statements underestimated his total net worth.

"Did you ever think that the values were off in your statement of financial condition?" state attorney Kevin Wallace asked about the document at the center of the case, which the New York attorney general has alleged contained fraudulent valuations.

"Yes, on occasion. Both high and low," Trump said, appearing to surprise Wallace, who paused to allow Trump to continue his answer.

Compared to his sons, who largely testified that they deferred to accountants and lawyers, Trump portrayed himself as an experienced businessman who "was certainly more expert than anybody else" when it came to the value of his own properties.

Asked about properties like 40 Wall Street and a retail space near Trump Tower, the former president confidently used real estate shorthand to explain why he thought certain properties were undervalued. He also repeated that his brand value -- which was not included in his financial statement -- is worth billions.

"The most valuable asset was the brand value," Trump said. "I became president because of my brand."

However, Trump acknowledged that two properties -- his triplex apartment in Trump Tower and his Seven Springs estate in New York's Westchester County -- were overvalued and had to be adjusted in his financial statement.

"I thought the apartment was overvalued when I looked at it," Trump said, appearing to refer to a $200 million correction applied to his statement after Forbes magazine reported that he falsely stated the apartment was three times its actual size.

Asked about the change in the statement, Trump acknowledged the square footage mistake, which he blamed on a broker, while also claiming that the number was "not far off" from reality when you consider the square footage of Trump Tower's roof.

"It's a mistake … [but] there's a disclaimer clause so you don't have to get sued by the attorney general of New York," Trump said.

Trump made a similar admission about the $291 million valuation of Seven Springs.

"I thought it was too high and we lowered it," Trump said, though he could not provide specifics about the changed valuation.