To make your vehicle appear, you'll need a trainer. I recommend the following THIS TRAINERwhich for me is the best. You can also run around the city to find it in traffic, but that might take a bit longer!

If the vehicle is installed as a replacement ► navigate to the " Vehicle spawner  "Then look for it and make it appear.

If installed as an add-on ► select the " Spawn by name  "in the Vehicle spawner  "then enter the name you have given it in your CSD.

Your vehicle should now appear!

Don't hesitate to test everything: damage, opening doors, trunks, hoods, shattering windows, bullet impacts, first-person view meter, all lights, driving, player position, correct placement of each script dummy... etc... anything that could be corrected.

Don't forget that a mod is never finished! Don't be ashamed to publish your models, even if they're not necessarily finished. You'll have plenty of time to come back and update them later! Here's a small example of how a mod has evolved over several years and is now one of the most downloaded on GTA5mods, my LAMBORGHINI Reventon.

Write down every problem you encounter on a piece of paper, because believe me, you'll often forget to fix things once you're back in the software! Re-open Zmodeler and work on your model to correct every little bug or modify textures, mapping... etc. A vehicle is never perfect at the first spawn.