Okay under each nexus links for download's is a green bar that says download with manager. I been trying to figure out how to get it to work because it says allow app when I click on that big green bar, I have obmm installed right and everything. I'm trying to install cobl(Common oblivion) for I can get this castle mod by centurion. I don't know how to get a mod to the mod manager because I always use to use that green bar, but now i'm trying to figure out how to get cobl in the mod manager. Can someone help me? Please and thank you.

~Ezio Auditore~

That green bar you're refering to is NMM not OBMM. Just download the file manually and convert it into OMOD instead. Better yet look into using Wrye Bash if you can. It will probably save yourself a headache and time in the long run(This is from someone who stuck with OBMM until recently so I've been there). If you're interested there's a pictorial guide to get started. Don't be afraid to use Wrye Bash. It's not as complicated as you may think it is.

What's NMM because that green bar use to always load my files into the oblivion mod manager?

Nexus Mod Manager. You either use that (if it is optimal for the game and in this case, it's not) or you use something like OBMM instead. It does not matter what you end up using, just stick with one.

However, for Oblivion, it may be better in the long run to download them manually and install them using Bash. Whether you make it a BAIN or not is up to you. It will make later installs and uninstalls a bit easier if you do.