Add custom vehicles to FiveM server?

Hey!

I installed a FiveM server on my KVM server with Debian 11. I just about managed to get it working. Now I have the problem that I'd like to add custom stuff like vehicles and the like. Everywhere it says you should put the file in Mods/DLC/… or something like that, but I think that only applies to GTA itself, not to a FiveM server. So far, I've only found two LoreFriendly vehicles that I could put into the RESOURCES folder, and I couldn't spawn them. One was a whole pack, and FiveM always crashed as soon as I started the resource, and with the other vehicle, it displayed "… was spawned" but nothing happened. Otherwise, I usually only find a folder containing the dlc.rpf file, but nothing else. Can you install vehicles like that? FiveM is actually included in the title.

And regarding Lore-Friendly vehicles: Am I allowed to install ONLY Lore-Friendly vehicles on the server, even if I'm the only one on the server? If so, where can I get good Lore-Friendly vehicles for free? For example, when I search for FiveM in GTA 5 mods, I only find RL cars, but no Lore-Friendly ones.

Thank you very much and have a nice evening everyone!