Hello, so i just joined on gog galaxy,for play some games didn't know there was such a big community here and i would like to know some information on how it works exactly, it's like steam or what ?

Galaxy is a client similar to Steam, but it's fully optional. If you'd prefer not to use it you can download the "offline installer" files from the website instead.

Galaxy is sometimes needed for multiplayer and to mark your achievements if you want them.

I do not use Galaxy at all.

99.9% of GOG games are DRM-free.
That is, you can play them offline everywhere without launching a client.

Technically, Steam also have quite a lot of DRM-free games.
But you have to backup them all by yourself, and some of them may become DRMed in the future.

You can install the same game on your Linux computer AND that Windows computer as long as both are yours and then take your laptop with you as you travel across the world and you will still be able to play wtihout St...some client locking you out.

Now there are a few caveats.

Just because a game was designed for Windows 98 doesn't mean you can plunk it down on your Pentium II and expect it to work. The fact of the matter is, GOG is about getting old games to work on new systems and that can often break things.

There is no support for Windows XP any longer. You may try, but don't expect any official support.

As for now it is just a launcher for GOG games with some interesting features like auto-updates, playtime tracking, cloud saves (not for every game though) and a few more. You can still play your games with or without Galaxy, it is completely up to you. Most of time I'm on Linux, but when playing on my old Windows using the client only to track my playtime for that instance, rarely for cloud saves and updates.