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.

During a short cross-examination of the defense's real estate valuation expert, Lawrence Moens, state attorney Kevin Wallace attempted to highlight flaws in Moens' analysis that valued Mar-a-Lago at $1.2 billion in 2021.

Wallace noted that Moens' analysis added over $100 million in membership dues to the value of the property, while Trump's own statements of financial conduction didn't include the membership fees since they're refundable.

"Some get paid back, and some are nonrefundable," Moens said in response. "I don't know what their methodology is in those numbers."

Wallace also asked if Moens had a membership in the club he had been paid to value.

"Are you a member at the club?" Wallace asked.

"I am," Moens said, adding that he joined in 1995 or 1996. "I don't go too often. I don't like clubs," he said.

Moens described his process for valuing properties as comparable to a baker making a cake by taste, rather than a recipe. By his own admission, the process was not replicable or scientific.

"You're not running a process that is recreatable ... is that fair?" Wallace asked.

"That's fair," Moens said.

Like during his direct examination, Moens appeared confident and playful on the stand, even taking a job at the profession of a colleague mentioned in an email.

"I think he is still a liar -- I mean a lawyer," Moens said. "Sorry, I apologize, it was really low."