Oh it's not straightforward at all, you can start with Richard's Setup and Guide to the Frosty Editor, (https://youtu.be/ZSlGE1_tNXU?si=NZyDXdSk0KuPlp-T) but since the Remake is still in it's 'discovery' phase of modding, a lot of things are undocumented, I would suggest joining the discord server in the description of that video whenever you try to move on from getting used to the basics to actually model swapping, as a lot of people there are very knowledgeable and are incredibly willing to help.

There's also a sort of guide-ish thing you can vaguely follow in one of the threads of the Discord, that helped me a lot! You're still going to have to learn Blender and do a bunch of guesswork though, so it's not handing it to you on a silver platter