How do i make my own versions of cars

how do i make my own cars like a covet sedan or a 2 door pessima
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btw when i import the dae its not there

 

A LOT of changes in the model itself, and also A LOT of changes in the jbeam. If you are just beginning to learn both of these things, it will be very difficult/not possible to do this.

 

well i have become less derpy and im a big roleplay hater now and i am quite good at blender but JBEAM ahhhhhhhhhhhhhh help i guess