I highly recommend you get the mods from the official F2 discord server. It's under the channel . Look #Workshop for the Custom mods post and then click on the messages.

the link for the official gorebox discord server is under this video:

After you get the mods, unzip them and put them into your gorebox mods directory.

Your mods are located in this directory:
C:\Users\Max\AppData\LocalLow\F2Games\GoreBox\Mods

(For mac, for the C:\Users\Max\AppData part it's /Users/Max/Library/Application Support/ and then F2Games/GoreBox/Mods. Please Correct me if I am wrong)

The Max part will be the name of your pc username, I just put max as an example

Your mods will show up under Addons < Mods. Either restart the game or click the cycle button in the bottom right corner of your screen.

Make sure that your mods name doesn't appear twice in your directory or you will get an error

example : C:\Users\Max\AppData\LocalLow\F2Games\GoreBox\Mods\mod_name\mod_name\

(don't forget to extract your mod folders before you put them in)

I switched my operating system from Windows to linux recently and so I thought I should also give linux users a way to find their mods folder for gorebox.

For linux you want to go into the drive where you installed gorebox. Go to SteamLibrary/steamapps/compatdata. There will be a lot of folders with numbers, the id for gore box is 2027330, so go to the folder with that number. Then click on pfx then drive_c. After that just go to the same location as for a windows user, Max will be replaced with steamuser. Then put your mods there.
users/steamuser/AppData/LocalLow/F2Games/GoreBox/Mods