I tried to download mods but they won't do any thing.

First i downloaded obmm to hold my mods.

then i downloaded the mod i wanted but it said the file was not supported.

then it brought me to the obmm screen telling me i was a limited user and i don't know what that means.

so i need help on how to use mods basically.

its for oblivion on my PC

OBMM only supports OMOD files, so you either need to download an OMOD file or use OBMM's OMOD creator to make one from the downloaded mod archive. Basically: Create > Add archive and go from there. It's easy with simple mods (i.e. mods that have only one esp, for example). Which mod are you talking about?

I'm quite novice with mods also, so I can kind of identify with you. I found the FAQ pinned thread at the top of this forum just a wonderful resource. It taught me how to load/install OBMM, then how to create omod files to install mods. Just basically using that FAQ, I can install mods that are omods or I can create omods from mods that only have one esp. I guess I have to figure out how to create folders etc instead of just archives to get into more complex mods.

Limited user is a windows operating system set of restrictions/security. There are quite a few instances when modding where you will need to be on an administrator account.