I'm installing FOOK, and it says to not use WRP as these textures are already included with FOOK. I'm having difficulty finding how to remove WRP.

If you used FOMM to install the mod, then that will remove it.

Otherwise you have to find all the textures and meshes that came with the mod and remove them from the Data Files folder. If there is an ESP with that mod, it might be enough to just uncheck the mod and then redo your bashed patch.

Edit: I notice that you are new to mods, I certainly hope you have been using best practices to install these mods and get them to work with each other, particularly with FOOK and others like it. If you have not done so, start with number one and go through all his videos before you install another mod

https://www.youtube.com/watch?v=I-3c1a9cLL8

if it's just texture files FOOK should overwrite the other mod unless one or both use .BSA archive files but I would suggest installing any future Retexture mods via a mod manager so that you would have easy access to it's removal

I use Nexus Mod Manager, and I can't find the WRP anywhere in the program, to de-activate. But when I installed FOOK's optional files, it came asking if I wanted to over write files that WRP was doing, so I said yes to this. Hopefully this is good enough.