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's Mar-a-Lago Club was worth more than $1.2 billion in 2021 -- roughly double the value listed in Trump's statement of financial condition -- according to defense expert Lawrence Moens.

Describing Mar-a-Lago as a castle nestled on 17.6 acres of waterfront property, Moens said he determined the value by considering nearby properties and adding the total value of the club's 500 memberships, which in 2021 cost $350,000 each.

Between 2011 and 2021, Moens' analysis found that Trump undervalued Mar-a-Lago in his statements of financial condition -- but his analysis appeared to be based on Trump being able to sell the property to an individual to use it as a private residence, which the New York attorney general says Trump is prohibited from doing based on a 2002 deed he signed that would "forever extinguish their right to develop or use the Property for any purpose other than club use."

Judge Engoron only qualified Moens as an expert on the value of residential real estate.

Moens spoke with confidence about his ability to value real estate in Palm Beach, saying that he has sold billions of dollars of real estate since his first sale as a broker in 1982. Asked if any broker has sold more Palm Beach real estate than he has, Moens replied, "They don't exist."

"I am on the front lines everyday of selling properties, and I have a pretty good handle of what is going on currently in the market," Moens said. He later added, "My numbers are usually right."

Moens also put together a seven-minute promotional video about Mar-a-Lago, which was played during his testimony. Set to relaxing music, the video included high-resolution drone shots and dramatic panning shots of the property's amenities. After the video played, Moens highlighted details such as hand-carved stones, gold decorations that cost millions to construct, and other details that required years of work from tradesmen.

"I invited the attorney general's office to come see it anytime. The offer still stands," Moens said. "I will make sure he is not there when you come," he said of Trump.

Engoron appeared attentive to Moen's testimony -- but once Moens left the courtroom, he indicated that he wasn't as concerned about Mar-a-Lago's specific value as he was about whether it was misrepresented.

"I see this case about the documents -- whether the defendants used false documents when transacting business," Engoron said. "I am not trying to figure out what the value is ... I don't necessarily consider it relevant."