Add on troubles

Ok, here’s the deal.

I download some sort of mod, and put it in my add on folder like I’ve been told plenty of times. I put in some props and a map and there are not showing up in my game.

What am I doing wrong here?

I added Super mario galaxy pack, and peaches castle to my add on folder and still do not see them in my game.

Do the folders contain an info.txt?

I think the file is needed to be recognized as an addon, or something like that.

I found something that says info deep with in the folder.

What I’ve been doing is just slipping the zipped folder into the add on folder. I guess I should be pulling some stuff out of there.