How do i join? do i need a launcher or something?
You need to download Multi Theft Auto - a free multiplayer modification for GTA San Andreas:
https://mtasa.com/
Then you need to find this server: 178.33.54.30:20256
That's it!
it says i need to select a gta install directory, what does that mean?
Select your GTA San Andreas folder. You need the game GTA San Andreas for MTA to work.