I just want somebody to explain the connection in 2-3 sentences.

One of my dads friends made a comment about New Jersey politicians having 'ties to the Mafia' Not hard to have Mafia ties if you have anything to do with in real estate in New Jersey. Almost impossible not to actually.

Trump deals in New York commercial real estate. Of course there are Russians.

There's no public information making it clear that there is a connection.

US intelligence officials have stated that the Russians devoted resources to act against Clinton in the election.

There's lots of speculation that people involved in the Trump campaign coordinated actions with Russians. Stuff like timing releases of information or messaging on social media.

People have made the point that regardless of whether there was coordination, Trump and fake news did often end up talking along similar themes (but that can just be one following along with the other).

Correlation but not causation.

Not every issue is simple enough to explain in 2-3 sentences, especially when it involves many complicated threads and unverified (but compelling) evidence.