[1.10.2] Understanding model system

I'm new to models and rendering of items and blocks in Minecraft although I'm familiar with other things. I'm trying to start on doing a custom model for an Item but I'm clueless and I don't know where to start off. I want to make an item that has different textures (specifically rod and cap) depending on materials, and I want it to be flexible (i.e. others can get to add new textures). I'm about to make a registry to add parts, with a client-only method to store the textures of the added parts (after being already registered ingame somehow) but that's another topic.

Now what I want is to understand how would I go about making the model in the first place, I don't see valid mod code around (can't find?) because they're all outdated 1.8.9 or lower. I tried to dig through the code but a lot is happening there. What I'm trying to get is how the IBakedModel does the override thing, I saw that the clock implements an anonymous type of IItemPropertyGetter and I don't understand the 0.0-1.0 float usage and the mapping of it, I know it returns something about the time of the clock depending on world ticks, but the way the matching happens in ItemOverride is confusing.

I also saw IModel and it's children in forge and it uses it for dynamic buckets, it made me confused to what I should use when. and what to implement to get my thing to work. Where should I start?