Copy the modded file back into the .depot folder, overwriting the original. Immediately change the file permissions to 444 (Read-only). This prevents the game from overwriting your edits as soon as you start a race.
Never, ever edit a file on the same account you use for Facebook login or purchases. Use a virtual machine, a second device, or accept that you are racing towards a ban.
Open your editor app. Click "Load File." Navigate to the .depot folder and select character.2.dat . The editor will scan the binary and display a user-friendly interface.