Former President Trump has arrived at the courthouse in lower Manhattan.

He stepped out of his motorcade, waved, and walked into the side entrance.

A small group of supporters and protesters both cheered and booed his arrival.

Former President Trump is en route to the courthouse in lower Manhattan for this morning's proceedings.

The former president left for the the courthouse from Trump Tower in Midtown Manhattan.

Court this morning may start with a hearing over what prosecutors can ask Trump during cross-examination should he take the stand later in the trial.

The judge would hear arguments from both the people and the defense. The proceedings would then move into jury selection later in the morning.

Prosecutors have indicated they would want to cross-examine Trump on approximately "thirteen different court determinations," including the recent civil finding that he sexually abused columnist E. Jean Carroll, the criminal conviction of the Trump Organization last year, the finding that he committed a decade of business fraud, and the dissolution of his charity, according to sources familiar with the matter.

The hearing -- known as a Sandoval hearing -- is standard practice before jury selection and typically occurs when a defendant signals a willingness to testify.

In a filing last month, Trump's lawyers requested a Sandoval hearing to limit the scope of Trump's potential cross examination, if he opted to testify.

ABC News' Katherine Faulders contributed to this report.

Former President Trump will leave his Trump Tower apartment in Midtown Manhattan this morning and travel down to lower Manhattan for the first day of jury selection in his criminal hush money trial.

The proceedings come after Trump unsuccessfully tried three times last week to delay the start of the trial through the filing of appeals.

As a defendant in a criminal case, the former president will be required to be in court for the entire trial, which is expected to take six to eight weeks.

Former National Enquirer publisher David Pecker, back on the witness stand, pointed at Donald Trump and flashed a smile when he was asked to identify the defendant. Trump turned his chin up and grinned at his longtime friend.

"I met Mr. Trump at Mar-a-Lago," Pecker said. "I've had a great relationship with Mr. Trump over the years."

That relationship started in 1989 when Pecker wanted to start a magazine called Trump Style.

"He was very helpful in introducing me to other executives in New York. He would always advise me of parties or events that I would go to," Pecker said, adding that Trump was among the first to congratulate him upon acquiring the National Enquirer.

Pecker described how Trump became a "major celebrity" after launching The Apprentice and later Celebrity Apprentice, and how the National Enquirer was there to juice Trump's profile.

"He was always kind enough to send me the content showing the ratings and I was able to publish that," Pecker said of their "great mutual beneficially relationship.

Pecker said he considered Trump a friend from 2015 to 2017, calling him by the familiar "Donald," as he pursued the White House for the first time.

"After he announced his run for the presidency I saw Mr. Trump more frequently, maybe once a month," Pecker said. The two spoke "maybe once every couple of weeks."

Pecker recalled meeting Trump in his office when his assistant brought a batch of invoices and checks to sign.

"As I recollect the entire package was stapled together," Pecker said.

"So you observed him reviewing an invoice and signing a check?" prosecutor Josh Steinglass asked. "That's correct," Pecker responded.

"I would describe him as very knowledgeable, very detail-oriented, almost as a micromanager," Pecker said.

When Steinglass asked how Trump was with money, Pecker responded, "He was very cautious and very frugal."