Menu help!

I have my menu bar set up and added duplicates of an item and don't see how I delete the duplicate without deleting the whole category or page. I'm sure it's pretty basic but not quite seeing it. Also when I changed my theme and I upgraded from a regular blog to the MUWP my Daily Theme automatically added my categories how do I customize those menu tabs. They seem to be different, they are darker and only have 7 categories but I think I could fit a few more on the top row. Just wondering if that is a different setting. Thanks for your patience with me.