Alright, this is a bit of a mistake that I've made in the description of the mod. If you want to change your keybinds, you can simply go to the Controls Tab.

However, if you want to configure morphs, you'd have use datapacks. A tutorial on how to do that can be found on this GitHub Repository in the README.md file.

By the way, if you wonder why I didn't choose to use a mod config but data packs instead, I simply think that data packs are more suited for this kind of configuration, as config files quickly get really messy and hard to read. Plus, you can only use one config file for a mod, but you can use multiple data packs, so that is also an advantage that data packs have over mod configs (in this case).

Anyways, that's it, I hope that I could help you out.
Have a good day.
-Budschie