as I can put two cars on the same screen

Hi good morning wondering how I can do to put two cars in the same game thanks : P

 

You mean this: http://wiki.beamng.com/Spawning_Vehicles ?

 

And how do I controll them or let crash?
I spawned like 2-3 other Vehicles. When I press TAB or SHIFT+TAB I can't control my current car anymore and the camera does not AIM the car I drove (when I drive away from spawned car, the camera jumps than near them) and I can toogle them (like 2-3 times till it comes back to my first car) but I can't move the vehicles? Also I cant crash into them? My car just drives through them...
I tried like everything to check or uncheck in the vehicle menu when I press on the new spawned... Any help?

 

Are you using the techdemo? Multiple vehicles is disabled in the techdemo I think.