Donald Trump's motorcade has arrived at the New York State Supreme Courthouse in lower Manhattan.

Court is scheduled to get underway at 10 a.m. ET, with Trump scheduled as the day's only witness.

Donald Trump, in New York, had a prep session with his lawyers Sunday ahead his testimony, sources tell ABC News.

Trump's mood during the session fluctuated between fits of anger regarding the case and being "in a good head space," according to sources.

The former president "can be a good witness if he stays focused," one source said.

Former President Trump is due in court to begin his testimony in his $250 million civil fraud trial at 10 a.m. ET.

Hundreds of members of the news media are huddled outside the New York State Supreme Courthouse ahead of Trump's arrival, with some having waited overnight.

After multiple in-court disputes about communications between him and his law clerk, Judge Arthur Engoron modified his limited gag order to cover attorneys in former President Donald Trump's civil fraud trial.

"Defendants may reference my staff as is appropriate to ask about scheduling issues or the management of the trial, which is an integral part of their jobs. What they may not do is to make any further statements about internal and confidential communications (be it conversations, note passing, or anything similar) between me and my staff," Engoron wrote in his supplemental limited gag order on Friday.

Engoron wrote that defense lawyers Chris Kise, Alina Habba, and Clifford Robert made "repeated, inappropriate remarks about my Principal Law Clerk, falsely accusing her of bias against them and of improperly influencing the ongoing bench trial."

The attorneys have raised multiple arguments during the trial that Engoron and his clerk passing notes between each other suggests impropriety and is distracting. Going forward, if the lawyers want to object to communications with his clerk, Engoron advised that they refer to the order as a "blanket statement."

"This gag order is as narrowly tailored as possible to accomplish its purpose, which is to protect the safety of my staff and promote the orderly progression of this trial," Engoron said.

To justify the safety threat, Engoron added that his chambers has received "hundreds of harassing and threatening phone calls, voicemails, emails, letters, and packages" since the start of the trial,

The judge threatened "serious sanctions" for violations of the extended order.

State attorney Kevin Wallace concluded his direct examination of the New York attorney general's second and final rebuttal witness amid frequent objections by defense lawyers.

Lewis attempted to explain how Donald Trump's statements of financial condition failed to disclose that he did not conduct a discounted cash flow analysis, contributing to the over-valuation of some of his assets.

"There is no mention of discounting or future value in the disclosure," Lewis said, disagreeing with testimony from defense expert Jason Flemmons -- as well as former Mazars USA accountant Donald Bender, who testified as a state witness.

“Are you impeaching your own witness?” Engoron asked state attorneys regarding whether Bender’s testimony should no longer be considered credible.

"We didn't feel the need to," Wallace responded.

Lewis also suggested that Trump's external accountants at Mazars had less of an obligation to highlight issues that Flemmons suggested, since they were only conducting a compilation report rather than a more intensive audit. While Mazars had an obligation to flag obvious issues, they were not responsible for ensuring Trump's statements were compliant with generally accepted accounting principles, he testified.

"If while doing the compilation ... something comes to the attention of the accounts that could be a GAAP departure, they have a responsibility to bring that issue to the client," Lewis said regarding generally accepted accounting principles.

During the hour-long direct examination, defense lawyers objected at least 14 times, successfully interrupting the line of questions.

"I am lost," Engoron asked at one point. "Can you put this together?"

The parade of objections visibly irritating Wallace, who voiced his displeasure.

"Petulant outbursts don't really play well in the courtroom," quipped Trump lawyer Chris Kise in response.