How to install a mod on disk

[Discordio]

I have the game on disk and have no idea how to install mods or if its possible. I looked up if it is, people say yes but not how. I've seen some saying go to the doom 3 folder and put the mods in the base folder, but i don't see it. Also if I try to change anything in the games folder it says "Insert a writable disk" and shoots out my game...

[Smokey]

You shall not install the mod to doom 3\base
only to doom 3 folder (never mess with the base folder)

maybe i can share my mod´s, if its ok with the one making them for me!

ps. its made for my screen size 1080x1920 and works with 59hz 60hz 120hz :)