What I am going to do is show you a copy of the default q3config.cfg file and then explain just a few items you will want to edit for your preferences. A very brief but informative description will be used.

Not all of these settings will be in all Quake III based games but most will be. There will be options in the newer games that are not shown here. If it is an item to be simply enabled or disabled then 1=true or on, 0=false or off.