The configs.ini file in your addons/amx/config folder contains a list of config files on your server that may be run from the Configuration Menu. This is enabled by using the amx_cfgmenu command and can be useful when starting a match, or for any special requirements you have. This is what the default configs.ini looks like:
(Note that a semi-colon ; was inserted at the beginning of some lines. This prevents them from being used.)
Adding additional entries to this menu should be the same as the lines in this file. Just change the name field and the file name (path too if applicable) to meet your need. Let's say you wanted to try out some deathmatch style maps in Counter-Strike, and edited a small config that had cvars in it to turn off the freeze time, friendly fire, and some other things. If this config was called deatchmatch.cfg, this is what the entry would look like in the config:
This menu is accessed in the game by typing amx_cfgmenu in the console. Or by binding a key to that command. The menu will show up on the left side of your screen while playing. It looks like this:
Just select the number of the config you want to be exec'd and that's it. Any changes made to the configs.ini file will show up after the next map change or server restart.