I don't understand all the Manaport and Cohen talk

The TV newsies are all excited about it.  Even Fox News who ought to know better. Me, I don't understand what either of them are accused of doing, I don't know if what they are accused of is a real crime, and I don't understand how this relates to Trump, other than both of them used to work for Trump.   Back in 2016, before Trump got elected, it isn't illegal to do a real estate deal in Moscow.  Might be stupid, because you cannot take Russian real estate out of the country, and inside Russia there are no courts that can protect your investment from seizure by the government.   But it ain't illegal for Americans to do business in Russia.