Gasps were heard in the overflow courtroom when Hope Hicks was called as a witness on Friday in Donald J. Trump’s criminal trial in Manhattan, an audible sign of the anticipation as Mr. Trump’s former press secretary and White House communications director took the stand. Her testimony ended the trial’s third week in dramatic fashion.

In nearly three hours on the stand, Ms. Hicks described the impact on Mr. Trump’s campaign of the so-called “Access Hollywood” tape, in which Mr. Trump bragged about grabbing women’s genitals. As soon as the tape was disclosed in October 2016, Ms. Hicks said, she knew it would be “a massive story.”

Taking the stand under a subpoena, Ms. Hicks said she was nervous, and at one point, early in the cross-examination, she broke down in tears.

The Manhattan district attorney has charged Mr. Trump, 77, with falsifying 34 business records to hide a $130,000 payment to Stormy Daniels, a porn star who says she and Mr. Trump had a tryst in 2006 while he was married. Mr. Trump, the first American president to face criminal prosecution, has denied the charges and says he did not have sex with Ms. Daniels. If convicted, he could face probation or prison time.

Here are five takeaways from Mr. Trump’s 11th day, and third week, on trial:

Ms. Hicks, now a communications consultant, testified to her fast rise in the Trump family orbit, going from working for his daughter Ivanka to press secretary for Mr. Trump’s campaign. It was in that role that, in October 2016, she had to confront what she called the “intense” fallout from the revelation of the “Access Hollywood” tape.