Colison problem

Hi, I have a question for you. I'm new to BeamNG, and I have a son who really, really wants me to install some models into the game — he loves cars. But I’m having a bit of a problem. I downloaded some models from Sketchfab based on his favorite cartoons and games. Unfortunately, they don’t have any collision.I read online that the issue might be with the mesh in Blender, but I honestly have no idea how that works. Could someone help me fix this or check if these models even have a mesh?
Thank guys!

 

Is there a jbeam?

 

Whats is that?
--- Post updated ---

Oh i just google it and how can I check it to see IF my download models have Jbeam

 

They wont

 

oof, yeah
for that, you would have to learn how to make whole car mods (maybe this can help)
or you can (like most people) download stuff from the forums and in-game repository
i also suggest taking a look at this, if you are completely new to the game