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.

Standing in the courthouse hallway where his father earlier railed against his civil trial, Eric Trump echoed his father's attacks on the New York attorney general and the case levied against his family, following the adjournment of court for the day.

"We have an unbelievable company. We have some of the best assets anywhere in the world. We've never had a default. We've never missed a payment," Eric Trump said of the Trump Organization.

Like his father, he described the case as politically motivated and decried the involvement of his family.

"They've dragged Don and I and Ivanka into it as collateral damage," he said.

Later, addressing reporters on the courthouse steps, he said that the state's efforts should be focused elsewhere.

"Let's get the murderers off the street. Let's take care of the crime. Let's rebuild our infrastructure. Everywhere you drive in New York, you hit a pothole and your car gets destroyed," he said.

Donald Trump agreed to "enhanced monitoring" of the Trump Organization's finances after the company's independent monitor flagged cash transfers of roughly $40 million over the last 10 months.

Former judge Barbara Jones, the independent monitor requested by the New York attorney general in the case, wrote in a letter to Judge Arthur Engoron that she had identified three separate cash transfers of more than $5 million, totaling approximately $40 million. Jones said the transfers included $29 million in tax payments and roughly $10 million for insurance premiums.

"We have discussed with Defendants why these transactions were not previously disclosed, and I have now clarified (and Defendants have agreed) that all transfers of assets out of the Trust exceeding $5 million must be reported," Jones wrote.

Jones also requested information related to an intercompany loan and flagged the delayed disclosure of tax returns for six of Trump's entities, which defendants acknowledged as their mistake.

"Defendants continue to cooperate with me and are generally in compliance with the Court's orders, and have committed to ensure that all required information, including tax information and cash transfers, are promptly disclosed to the Monitor," Jones wrote.

Addressing a report she issued in August about incomplete financial disclosures by the Trump Organization, Jones added that the Trump Organization took additional steps to remedy and disclose the issue.

"By taking these steps I believe Defendants have resolved the issues identified in the August Report, subject to ongoing monitoring," Jones wrote.