download the one for your system, and then that is the client for the game. If you are on windows, download qw230.exe or qw230.zip. You can pick between the openGL client and the software client. Use the readme to troubleshoot any problems. If you cant get the openGL client to work, use the software client. The game will not run without the game data. You can download this on steam, or pirate it online. The game data is a file called "pak0.pak". Read more about it here: https://quakewiki.org/wiki/pak0.pak
Ok there is a solution. Jump on discord quake channels, ask for someone to remote assist you and help you, using something like teamviewer. This is something that anyone with reasonable IT skills can fix for you.
Someone can give you a link to the discord Quake channels (I don't have them on hand, but google can probably find it)
https://discord.gg/PQhU7 but he could try IRC too I guess
Edit: whoops I think this is the quake live discord channel but nvm, you could find someone here too
Edited by Brancaleone at 08:01 CDT, 27 August 2016