See the right-hand navigation bar to select a guide topic.
A few things to note up front:
These guides should still be on-point for handling the original Quake engines. But when it comes to the specific features of modern Quake engines, I've let these guides get out of date. There's some errata posted over on the Steam forums but that may be getting stale at this point too.
I'm not sure when/if I'll be in the frame of mind for a grand rewrite of this stuff. My "help folks play Quake" energy is entirely taken up by the Quake Singleplayer Starter Pack currently, which is a project that is a bit more focussed and practical.
Regardless, if you've got comments about the guide contents you can still send me an email, especially if you see some info about the original Quake engines that needs correcting.