Hmm? To install that file, all you should have to do is install the Oblivion Mod Manager, extract the omod file that is in the mod rar, load into the manager and click install. Shouldn't be so hard.
Anyway, TESNexus is good, both for finding mods and the forum, but I recommend the official forums as well:
http://forums.bethsoft.com/index.php?/forum/87-iv-oblivion/, the community is kind and helpful, and there are lots of explanations on how to install the mods. Also, READ THE README FILES, they usually has all the instructions needed.
Sorry if I won't make a complete guide for you right now, was just out and my fingers are frozen solid, can't type well >,