Donald Trump faced forward and did not appear to make eye contact with any jurors as they entered the courtroom and took their seats in the jury box.

Before any of the lawyers in the case could speak a word, Judge Merchan launched into a lengthy speech outlining how the trial will work.

"We are about to begin the trial of People of the State of New York v. Donald Trump," Merchan told the 12 jurors and six alternates.

Merchan emphasized that the burden of proof rests on the prosecutors and that jurors should presume that Trump is innocent. A guilty verdict requires that each juror determines that the state proved their case beyond a reasonable doubt, Merchan said.

"The defendant is presumed to be innocent," Merchan said. "It is not sufficient to prove that the defendant is probably guilty."

Merchan attempted to set expectations for the jurors, only two of which have ever served on a jury before. For example, Merchan told the jurors not to expect the lawyers to launch into lengthy speeches outside of the opening and closing statements.

"That happens in TV and in movies, but it doesn't happen in real trials," Merchan said.

Judge Juan Merchan ruled that if Trump takes the stand, prosecutors can question him about a number of previous legal issues -- but the judge limited the scope of the cases and the extent to which prosecutors can question him about the facts of those cases.

The ruling is a mixed bag for Trump, who had sought to entirely block questioning on these previous issues if he takes the stand.

Judge Merchan ruled that Trump can be questioned by the DA's office on six determinations from four previous proceedings, including aspects of his New York civil fraud case and the gag order violations there, as well as both verdicts in the E. Jean Carroll cases and the 2018 Trump Foundation case.

Prosecutors had originally asked to question Trump about six different proceedings with 13 total determinations.

Merchan said with his ruling, he has "greatly curtailed" how much prosecutors can discuss the underlying facts of those cases.

"The court cautions the defendant that this Sandoval ruling is a shield, not a sword," Merchan said.

Prosecutors told Judge Merchan that they need 40 minutes for their opening statements.

Defense attorneys told the judge they need 25 minutes.

The judge also announced that court will break at 12:30 p.m. ET today, after a juror had a toothache and got an emergency appointment this afternoon.

Court had already been scheduled to end early today, at 2 p.m. ET, due to the Passover holiday.

Judge Juan Merchan announced there is an issue with Juror No. 9 -- who, according to Merchan, "was concerned about media attention" of the case. According to Merchan, the juror "wasn't 100% sure" they could serve.

Merchan said they would speak to the juror in chambers to "find out what the issue is and see if this juror can continue to serve."

After a brief sidebar, the judge announced: “Juror No. 9 is going to remain with us.”

There are six alternate jurors seated in case any of the 12 jurors cannot serve.

With Donald Trump following along from the defense table, head cocked slightly to the side, David Pecker described the negotiations conducted with Karen McDougal to purchase the exclusive rights to her story about an alleged year-long relationship with Trump.

Pecker said that Trump's attorney Michael Cohen authorized negotiations to begin, then during those negotiations, "Michael was very agitated," constantly asking "Why is this taking so long?"

"To purchase the lifetime rights to Karen McDougal was going to cost $150,000. Plus Karen wanted to restart her career. She wanted to write for the celebrity magazines. She wanted to be on the cover of the life and fitness titles. She had a major problem when her breast implants were removed and she wanted to write about that," Pecker testified.

Pecker said he asked Cohen, "Who is going to reimburse me for this?" He said Cohen responded "Don't worry about it, I'm your friend the boss will take care of it.'"

When prosecutor Josh Steinglass asked Pecker who "the boss" was, Pecker answered "The boss would have been Donald Trump"

Prosecutors then displayed for the jury the contract with McDougal, dated August 5, 2016. It awarded AMI, the Enquirer's parent company, the rights to her story of a relationship she had "with any then-married man." Pecker said "she was referring to Donald Trump."

Pecker testified he needed to "validate" the amount of money AMI was going to pay, so the contract included other provisions, like having McDougal write monthly columns on aging and fitness.

"With respect to campaign laws, I wanted to have the contract be a record that stipulates the services she was going to perform for American Media had a basis for it, the $150,000," Pecker said.

"Was it your primary purpose to buy the life rights?" Steinglass asked. "Yes it was," Pecker responded.

"Were the other provisions to disguise the true nature of this contract?" Steinglass asked. "Yes," Pecker replied, letting out a sigh.