0. Go to the game's main folder, then go to Content/SeriousSam3/

1. Open up one of the All.gro files (it's a zip)

2. Inside them, go to Content/SeriousSam3/Music

3. Take note of the names of the music files, but don't do anything else in the gro file, as you cannot modify them.

4. Now go back to the game's main folder proper. Notice that outside the gro files, the directories are basically the same.

5. Inside Content/SeriousSam3/ , create a "Music" folder, and put your songs there with the same name and format as the original ones (of course, if your music is not in ogg format, you need to convert them to that).

6. Technically, you are done. You can try it out if you start the Modded Mode of the game. It doesn't hurt to test if it works anyways.

7. If you want to upload it to the workshop, you need to create a gro file. You do this by putting your music in a zip file. Note that the zip must contain the proper folder structure (just like the All.gro files), as in your zip should have the Content/SeriousSam3/Music folders. After you're done, just rename the zip to a gro. No conversion needed.

8. The best after this if you delete the music outside of the gro, and then name the gro something like "Z_NanomachinesSon.gro". The Z_ makes sure that it's loaded last while the game is booting, so it properly mods the game. If everything works, then it's time to upload it.

9. Open the Serious Editor 3. It's located on the Tools tab of your Steam Games Library.

10. Inside it, go File, and click on Upload Content to Steam. Everything after that should be self-evident. The content file you upload is obviously the gro file.

Have fun!

Thank you! I'll definitely give this a shot, it seems simple enough to do so this'll be pretty damn fun o/