Many mods seem to work just fine without any messing about. The link you posted has solid information - just read posts #10 and #12 by JediKnight007.
The basic gist of it is that you start with a Quake ‘rom’ directory containing the main quake folders:
To add a mod, just make a new folder in the ‘Quake’ directory and place the mod files inside. For example, lets say we want to play ‘Contract Revoked’:
It should look like this:
To run the mod, just add the following lines to your ‘Quake1.lpl’ playlist file:
Quake MOD: Contract Revoked
Now you can select and run the mod from the XMB menu (or whatever you’re using).
If a particular mod has a music pack (https://www.quaddicted.com/files/music/), just create a ‘music’ folder inside the mod directory and copy over the .ogg files (you might need to convert the files to ogg format first…)
If a particular mod has coloured lighting files (https://quakewiki.org/wiki/External_Lit_And_Vis_Files), just copy the relevant ‘maps’ folder to the mod directory and enable ‘Colored lighting’ in the core options. (Most of these lit/vis bundles work fine, but some don’t… YMMV)
Note that some mods have nuances that require special attention, so you do have to go through them on a mod-by-mod basis and check the readme.txt files and stuff. Off the top of my head, here are a few of examples:
This doesn’t have a normal start map, so in the instructions it tells you to open the console and type ‘map bbstart’ to begin. This is no good with a controller, but you can get around it by creating an ‘autoexec.cfg’ file in the mod directory with the following contents:
You can then run the game normally from the XMB menu.
This commercial addon is a pig because it requires a bunch of patches that are almost impossible to find…
But if you do get it working, the game itself has an additional non-standard control input - press ‘1’ to cycle through the utility belt. You have to map this to your gamepad manually by adding the following line to the ‘autoexec.cfg’ file that comes with the game:
bind "JOY_R3" "impulse 1"
This commercial addon sorta-kinda works (the game speed glitches out sometimes, but whatever…). The point is that it has a very non-standard control method that you have to assign manually by placing the following hack in an ‘autoexec.cfg’ file inside the mod directory:
alias +walkfast "cl_forwardspeed 400;cl_backspeed 400; cl_anglespeedkey 0.5; cl_sidespeed 400";
alias -walkfast "cl_forwardspeed 200; cl_backspeed 200; cl_anglespeedkey 1.5;cl_sidespeed 200";
bind "JOY_A" "impulse 13"
bind "JOY_Y" "impulse 14"
bind "JOY_R3" "impulse 30"
i.e. In order to remap a controller button that is already assigned by RetroArch, in the ‘autoexec.cfg’ you have to:
- unbind it
- unbind it again
- bind it
Anyway, I hope that helps some. Note that a number of mods will never work (typically ones that require increased limits and suchlike), so some experimentation is required…