How do you order fast food?

I want to go to taco bell and order their Nacho BellGrande (originally with beans, beef, cheese, tomatoes, and sour cream) with only extra beef and extra cheese. How should I order that? I don't want them to think I want beans, extra beef, extra cheese, tomatoes, and sour cream, I just want only extra beef and extra cheese. My Taco Bell does mess up a lot, so I want to know what you think the clearest way of ordering that would be. Thanks, LOL.