List of all mods:
Go to your Steam folder then add this location onto your address bar:
\SteamApps\common\Game Dev Tycoon\mods
Next just select the .zip archive that contains the mod and extract the folder onto the .mods folder.
Then just boot the game up, select the mods in the mods menu and play the heck out of the game!
Discuss any mod-related issues or glitches in the respective thread, not here.
If you can’t manage to install it, (for example the mod doesn’t appear in the mod selection) reply here, please.
Default directory of the game (Steam):
C:\Program Files\Steam\SteamApps\common\Game Dev Tycoon