Making Mods...

[Golden Mods | KL]

I'm currently trying to make a mod for GTA V. I'm wanting to do a modified vehicle from GTA IV, I have Zmodler but am still unfamiliar with how to use it. I see videos everywhere on how to convert vehicles and this and that but the video tutorials always start with a z3d. file. But I dont know how to get the model to just a z3d. file. Like how do I take a GTA IV vehicle files and make that a z3d. file so I can convert it?
Golden Mods - KL
Thanks.