First, download and unzip the mod you want to install. After that, look for a file that ends in ".gro". Copy it.

Next, you'll have to find the folder where Serious Sam 3 is located.

To do this, go to your C drive. When you're there, find "program files" or "program files (x86)" and click on it. After that, look for a folder called Steam. Open it, then look for another folder called "steamapps". When its open, find another folder called "common". When you're there, you should see a folder called "serious sam 3". Open it. You're now in your base SS3 folder.

If you installed the game somewhere else, ignore this. Instead, go to where you installed it.

Now that you're in your SS3 folder, find a folder called "Content" and open it. From there, open the "SeriousSam3" folder.



This is where you should be at.

You're almost done! Now, paste the .gro file you copied earlier into the "SeriousSam3" folder.

Congrats, you've now installed your mod! The last thing you need to do is get it running.

Good job so far! The last thing you need to do is run the game.

In order to do this, click on SS3 in Steam. When you do, a menu will appear that has two options. Select the "Play Moddable Version" option, then hit "Play".



This is what should be appearing when you start SS3.

This will start the moddable version of the game, which is a special version of the game that lets you run mods, but disables achievements and the leaderboard. Now, check to see if your mod works. If it does, congrats! You've just installed a mod manually!