Nitro Stunt Racing

How to register to import/export profiles for the Stage 1, here at nitrustuntracing.com (where?) or in the agme (where?).

I don't understand, could you be more precise ?

When you register, you can use up to 4 profiles. Each profile is automatically exported when you do an update.
If you reinstall the game on another machine and register with the same license info, you'll get your profiles back automatically.