Installing mods to Bethesda games is usually very straightforward. The challenge of it comes when you want to install 100 mods at once. If you only want to install that single mod it should be as simple as moving the files where the readme tells you to. (quality mods always have installation instructions)

As for OpenMW compatibility search the openmw page, they have a list of supported mods. It's probably supported though, since it's a simple texture mod from what i can tell.

Probably good resource to check for compatibility/tips:
https://modding-openmw.com/

As far as I can tell there are not instructions included with the MOD. I don't see the enhanced texture pack listed on the site you linked. I am guessing it is not supported then?

If it's just a texture replacer with a simple Data Files/Textures structure, you should just be able to merge the contents with your Data Files folder. Check any ESP/ESM files under your launcher and you should be good.

However, if it depends on MWGE or MWSE, then it is NOT compatible with OpemMW. (If you see any .dll or .exe files in the pack, it's a good indication that OpenMW won't support it.)