How do men have sex with men?

Mostly like everybody else.

Yes, there are certain differences given that there are two penises and no vagina, but broadly speaking, things are not that different.

Men start by flirting. Then they kiss and caress each other. Next, as the sexual excitement mounts, they move to more intense foreplay. 

They might rub their bodies and genitals against each other (dry humping or frottage), mutually masturbate, perform oral sex on each other, or have anal sex.

Then, like everybody else, if they are in the mood, they might cuddle for a while and fall asleep.