Sure thing Phan! And thanks for that link, I forgot some people don't have 7-Zip.
Now I will put these steps as understandable as possible for anyone that needs help with this!
Step 1: Download the link that Phantom posted. (Download my link if you use 7-Zip.)
Step 2: Extract MP3 files to the root of your Re-Volt folder.
Step 3: Go to your 'levels' folder. For example let's choose 'nhood1'
Step 4: Find the 'Nhood.inf' file. (It's different depending on what track you choose). Inside the file you will find track name and so forth. Most importantly find the line that says 'MP3" (If there isn't one, create a line for it.)
Step 5: See how it says 'nhood1.mp3'? That's where Re-Volt detects the music file that is going to played with you start the track! To change this, go back to the root of your Re-Volt folder and look at your MP3 files that you downloaded earlier. Pick whatever one you like, for example I choose 'Out of Control N64.mp3' (Don't forget to right click the MP3 file and copy the name of it.)
Also!! There are some key combinations such as 'CTRL + C and CTRL + V' rather then just right clicking the music file and copying the name, those combinations make it more easier and faster.
Step 6: Small step, all you have to do now is go back to the track folder you were earlier and click on the inf file! Then look for the 'MP3' line and copy paste your song name! It should look like this:
;--------------------------
;Revolt .INF file structure
;--------------------------
NAME 'Toys in the Hood';The name of the level as seen in-game
STARTPOS -14974. 88. 20489 ;Start position of the car
STARTPOSREV -13311. 37. 18925 ;Start position of the car
STARTROT 0.25 ;Start rotation of the car (0 - 1)
STARTROTREV 0.75 ;Start rotation of the car (0 - 1)
FARCLIP 24000 ;Far clipping distance (draw distance)
FOGSTART 23000 ;Fog start (slightly less than FARCLIP)
FOGCOLOR 80 144 192 ;Fog and background color
VERTFOGSTART 0 ;Vertical fog start (as in rooftops)
VERTFOGEND 0 ;Vertical fog end (as in rooftops)
WORLDRGBPER 100 ;RGB percent of original world gouraud
MODELRGBPER 100 ;RGB percent of original model gouraud
INSTANCERGBPER 100 ;RGB percent of original instance gouraud
MIRRORS 0 0.75 0 256 ;Type - mix - intensity start - distance
MP3 'Out of Control N64.mp3'
REDBOOK 4 9
One last thing, don't forget to save!!
Well that's about it, if I missed something I will add it in this tutorial, hopefully you learned the ways to put custom music files on your track!