Oraxen is an open source plugin that allows you to add a bunch of custom items, blocks, armor and other things to a server. On top of that it also helps the user create a resource pack automatically. You can see the entire Oraxen wiki here, which has good instructions but it does not teach the user how a resource pack works. Everything Oraxen adds to a resource pack can be done by hand.
We are writing these guides because we have community members who asks us how to add models to the plugin, mostly because their wiki isn’t 100% straight forward and people might need easy step by step guides.
If you do not have the plugin yet, you can get it here.