First, you have to go to options. Then, click on the letters AUDIO SETUP. Now, you should see a screen with a radio volume adjuster, a Sound effect volume adjuster, Radio Equalization, Radio Auto-Tune, User Track Options, Radio Station, All Radio Stations, Restore Defaults, and Back. Not all of these aren't really important now, so ignore them. Just make sure to go to User Track Options, go to play mode, and make sure it's set to radio.

So, secondly, exit out of GTA San Andreas. Thirdly, go to Your Documents Folder, GTA San Andreas User Files, User Tracks, copy your audio file from any folder, and then paste it into the User Tracks folder. If you want to convert a youtube video to MP3, copy the URL using CTRL C. This is what a VALID URL looks like. https://www.youtube.com/watch?v= (numbers and letters) . Then, Paste it into a URL to MP3 converter of your choice . Make sure the file it outputs is an MP3. Last step, open up GTA San Andreas again, go to Options, User Track Options, and click Scan User Tracks. The game will now scan your files to make sure they are valid for playing on the radio. Congratulations! If everything is good, you should be able to tune in to User Track Player on all stereo radios to hear your glorious custom music! If you have any problems caused by this guide, do not hesitate to comment down below.