Couple of ways to do that.
1. Click on the Community tab in the header (where you see User CP).
2. Click My Garage.
3. Add a vehicle or service record etc.
Next option...
1. Click User CP.
2. On the left side, click Edit Your Details.
3. Scroll down to "Please click here if you want to modify your vehicles in your garage."
4. Add a vehicle or service record etc.
If you want to modify a vehicle name, add special wording behind it like "TRD" "V8" etc., you will need to either delete the current vehicle or PM me with your request and I'll take care of it free of charge.
If you've already entered in a dozen service records and don't want to delete the vehicle, contact me, I'll fix it however you want it.
Hope that helps, let me know if you need something else. Sorry it took so long to answer your question.