The fourth week of Donald J. Trump’s Manhattan criminal trial veered from the salacious to the monotonous, and ended with a preview of a showdown coming next week: the long-awaited testimony of Mr. Trump’s fixer-turned-nemesis, Michael D. Cohen.

On Friday, Justice Juan M. Merchan asked prosecutors to tell Mr. Cohen to stop talking about Mr. Trump, after a defense lawyer told him of a recent TikTok video in which Mr. Cohen wore a shirt with a picture of Mr. Trump behind bars.

His request capped a week in which the jury heard a porn star’s lurid story of a 2006 sexual encounter with Mr. Trump but also less sensational, if potentially damning, testimony about Mr. Trump’s checks, invoices and ledgers.

The former president is accused of falsifying business records to hide a $130,000 payment to the porn actress, Stormy Daniels, just before the 2016 election, a payment meant to silence her. Mr. Trump, 77, has denied the charges and says he did not have sex with Ms. Daniels. If convicted, he could face prison or probation.

Here are five takeaways from Mr. Trump’s fourth week, and 15th day, on trial:

Stormy Daniels’s testimony could be critical.

For almost eight gripping hours, Ms. Daniels took the jurors inside the Lake Tahoe, Nev., hotel suite where she said she and Mr. Trump had sex, a detailed account that included everything from what was in his bathroom to her conflicted feelings before and after.

Initially, her testimony meandered, leading to interruptions and a warning from Justice Merchan to avoid tangents, as well as many successful objections by defense lawyers.