Hello my friends.I have installed gog galaxy and it says it is not connected to gog.com. But when I try to connect, it requests me a code. Where can I find that code, or how can I connect and play with my friens?

Try logging into Galaxy in the top of the screen. Use your username and password. If you have 2 factor Authentication enabled, you will have to type in a 4 character password that is emailed to your account email address upon attempting to login. The code is only valid for a short time. Once you've logged in, if you're still seeing that you "need a code" to connect a specific game, it's because you don't own the game in your GOG library and have purchased it from an illegitimate source (and it was removed for being a fraudulent key) or downloaded it from an unauthorized source (IE pirate). If that's the case, please purchase the game from GOG. If you want your money back from your original purchase, seek the refund through the site from which you purchased the game.