There are 3 ways:
1) Write your complete own UI module to replace the Unity UI module.
This involves writing the Makinom and ORK parts for the extension - best take a look at the Makinom and ORK source code projects for that.
2) If you're using Unity UI, you can adjust the module to your needs by changing it's source code (or making your own version separate from it by copying it and changing a few things).
3) Ignore ORK's UI and just build your custom one accessing ORK's features.
Basically don't use the built-in UI functionality like menu screens, HUDs, etc.