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.

Defense attorney Alina Habba, speaking to reporters outside court, said that an appellate judge's decision to temporarily stay Judge Engoron's limited gag order on Donald Trump would allow the defense team to continue raising issues with the conduct of Engoron's clerk.

Habba also said she saw no reason to advise Trump to refrain from attacking the clerk now that the gag order has been stayed -- despite Judge Engoron's concerns about his staff facing threats.

"There is not a day that I don't get a threat. It's just part of the game," Habba said. "If I put something out on social media, and I get a threat for it, which has happened to me every single day, I don't get to cry."

"Ms. James is continuing to disparage my client," Habba said, referring to New York Attorney General Letitia James, who filed the lawsuit against Trump. "And they were grasping at straws for a reason to say that the president should be gagged. There was no reason."

James did not ask for the gag order, which was issued by Judge Engoron last month out of concern for the safety of his staff after Trump made a false post about his clerk on social media.