Just Easy Step Directly to the point.
-First: Go in GTA San Andreas User File
-Second: Go in User Tracks
-Third: Paste any radio file or mp3 or any multiple mp3s.. on User Tracks
-Fourth: Open GTA San Andreas or SAMP.
-Fifth: Press ESC and go in Option
-Sixth: Go In Audio Setup And then go in User Track Option and click on Scan User Tracks( after this it will take 1 or 2 mins to scan)
-Seventh: Play User Track Player, you are done enjoy!