Thanks for the answers and especially that detailed explanation, Preach!

By the way, would someone be so kind as to give me a link to the code in question? I assume it's on github somewhere, but I always get confused looking for things there. Doubt I'll be able to understand much of the code, but I'd like to have a look anyway -- presumable that's the first step towards understanding it. 

This is as far as I get on my own (which I assume is the right place): https://github.com/id-Software/Quake/tree/master/WinQuake

I have no idea in which of the several files or sub-directories I should be looking, though... 

I believe this is the file you're looking for:
https://github.com/id-Software/Quake/blob/master/qw-qc/weapons.qc 

otp collected these Quake links for the Quake Mapping Discord - might be helpful:

QuakeWiki Modding Tutorial:
https://quakewiki.org/wiki/Getting_Started_Modding

QuakeC tutorial:
http://www.insideqc.com/qctut/

QuakeC Reference Manual in PDF:
http://pages.cs.wisc.edu/~jeremyp/quake/quakec/quakec.pdf

QuakeC Manual website version (with nice text formating):
http://www.cataboligne.org/extra/qcmanual.html

FTEQCC compiler:
http://fte.triptohell.info/moodles/fteqcc/

FTEQCC documentation:
http://icculus.org/~marco/quakec/fteqcc_manual.txt

Progs v1.01 source code:
https://github.com/id-Software/Quake-Tools/tree/master/qcc/v101qc

Progs v1.01 source code: (cleaned):
https://gitlab.com/quakec-v1-01-clean/quakec-v1-01-clean/commits/master

Progs v1.06 source code:
http://www.moddb.com/games/quake/downloads/quake-c-version-106

Hipnotic SDK:
http://www.gamers.org/pub/idgames2/more_idstuff/hipnotic/ 

The source Strogg-Sothoth linked is for quakeworld, just be aware that quake and quakeworld had slightly different calculations for weapon attacks (at least, the shotguns are different.)

The "progs 1.01 sourcecode" dumptruck linked is the original quake version which is also what almost everyone would use for playing single player maps. 

The "progs 1.01 sourcecode" dumptruck linked is the original quake version which is also what almost everyone would use for playing single player maps.

Brilliant, thanks! 

correction, the "Progs v1.06 source code" is actually what most people would play (but the difference is only bug fixes, not major gameplay changes AFAIK) 

The source Strogg-Sothoth linked is for quakeworld, just be aware that quake and quakeworld had slightly different calculations for weapon attacks (at least, the shotguns are different.)

Oops, my bad. 

(The four anonymous posts above were mine). 

Target "C:\Program Files (x86)\GOG Galaxy\Games\Quake\quakespasm\quakespasm-0.93.1_win64\quakespasm-0.93.1_win64\quakespasm.exe" -hipnotic -game quoth

Start inC:\Program Files (x86)\GOG Galaxy\Games\Quake\quakespasm\quakespasm-0.93.1_win64\quakespasm-0.93.1_win64"

I'm trying to play the ad mod but all I get is Quake start. Same when I try to play this mod. Tried Quake injector but even with java installed I get how do you want to open this file. 

lizard: try "-game ad" instead of "-hipnotic -game quoth" 

An observation from adding maps to Quaddicted:
There's no need to use BSP2 format unless the map is really really large and detailed - like Tronyn/Orl/ad_sepulcher type of stuff. Don't just switch format as soon as a warning message pops up. Engine protocol 666 can handle most levels that exceed vanilla (=protocol 15) limits.

More often than not you don't even need that. Frankly, I'm surprised how seemingly even the smallest maps are exceeding some limits these days. Then again, just an old geezer tilting at windmills. :) 

It occurs to me that there may be a misunderstanding that BSP2 is needed for features such as fence textures or detail brushed, so just to clear that up: it's not.

BSP2 contains no new features, it's only about raising format limits. So if you don't need raised limits, you don't need BSP2. 

I did try -game ad and after that didn't work I tried quoth. Same incident. 

Are your ad and quoth directories called "ad" and "quoth"? If they are called something like "ad_v1_70final" and "quoth2pt2full_2", rename them to "ad" and "quoth" and then try again. 

Didn't work but thanks for the help 

I'm trying to play the ad mod but all I get is Quake start

So if I understand you correctly, you are able to start Quakespasm and play regular Quake (without any mods), right? So try this: start Quakespasm, pull down the console (which you do by pressing the tilde ("~") key if you are using a US/international keyboard layout) and type "game ad". 

It says game changed to ad but quake start still comes up no ad anything 

Whats the name of the folder you keep all your arcane dimensions stuff in?

game "MOD FOLDER NAME"

so if your mod folder name is ADFINAL1_70 youll need to type that in. 

okay next step... find your quake directory in windows explorer, and make sure there is a folder called "ad" that is a sibling to your "id1" folder, and makes sure there are some subfolders in the ad folder called "maps", "progs", etc 

Thanks to everyone for your expert advice getting the ad mod working. Putting the extra stuff on the end of the command was the answer for me. ad_v1_50final. My ad folder which is in the quake folder just says ad. In side is the 2 zip files (mod and patch) and the unzipped files. I unzipped the regular file first then the patch. After I chose a map and entered it it said completed and just set there. Somehow I stumbled across the right shift key and the game started. I have no idea why the shift key unless it is in the cfg. file. But I never would have got it going without you guys helping out. It's not like the initialization file said to do it. 

https://store.steampowered.com/app/753590/Hellbound/ 

Any pros here? 

Are pros.