Trainer Car Spawner

Ok, so I’ve been messing around with Native Trainer and a few other trainers for a while now. I’ve been learning how they work and editing them a bit but something I’ve encountered is the fact that the Native Trainer car spawner does not work at all! I wanted to use it and strip it down so it only listed a few cars but before that I decided to test it and I found out it just doesn’t spawn the cars. Can somebody please tell me how I would go about spawning a car through a mod menu/trainer and maybe how to use custom input (like Lambda Menu)