Ok, this is gonna be a long haul....
Step 1. Go to addons folder (its in your blocklands folder usually under C:programfiles\blockland)
Step 2. Find the file that says "vehicle_jeep.cs"
Step 3. Make a copy of this file using the right click button. You should now have a file called "copy of vehicle_jeep.cs"
Step 4. Go into the file....you know what...let me try and make an animated GIF because this is too hard to explain.
EDIT: Change of plans. I'm gonna make a video tutorial showing you and everyone that wants to know how to make vehicles and I will do so from the beggining. May take awhile but I think everyone can benefit from it.