2. "Individual 1" mentioned prominently. These new documents contain eleven references to "Individual 1," which is presumed to be President Trump. Using what seems to be evidence from contemporaneous emails sent and received by Cohen, the court documents show Cohen discussed a possible 'business travel to Russia' during the 2016 campaign.
3. "Russian Official 1." While we know who "Individual 1" is, there is also a mention in the documents of "Russian Official 1," who is presumed to be the press secretary to Russian leader Vladimir Putin, Dmitry Peskov. The documents then lead right to Putin. "Individual 2 wrote to COHEN, "It's about [the President of Russia] they called today."
4. Cohen agreed to travel to Russia in 2016. While the trip never actually took place, the court documents show that Cohen agreed to go to Russia to work on the Trump Tower hotel project, as he was invited at one point by Putin's press secretary to a Russian government event in St. Petersburg, in June of 2016. "COHEN and Individual 2 discussed on multiple occasions traveling to Russia to pursue the Moscow Project."
5. "Individual 2." While there is no concrete identification of the person who was floating the possibility of introducing Cohen to both Vladimir Putin and Russian Prime Minister Dmitry Medvedev, many believe this person is Felix Sater, a Russian-born New York businessman, who has reportedly been cooperating with the Mueller investigation.
The details of the Cohen guilty plea can be found here.
The details of his plea agreement is available here.