The zip file contains a materials folder which contains folders hoi_dev_128 and hoi_moo, allowing you to install one or both of the sets of textures.

Just copy the desired folder(s) to C:\Program Files (x86)\Steam\steamapps\common\Team Fortress 2\tf\materials

These textures are used in jump_hoi, jump_bear, jump_cow and jump_moo

I recommend using texture scale .25 for all textures (making the dev textures 128x128 units) besides the hoi_moo/sky one which probably works best with texture scale 1