Mock up Beta is missing

I’m trying to use the Mockup Beta feature in Illustrator, but it's missing for some reason, so I can’t do the mock-up product. Despite watching many tutorials, I still don’t know why. Just in case I did something wrong: I downloaded an image to use for the product then used my own artwork designed on Illustrator as a logo. Is this the correct procedure to use for a mock-up? 

Thank you.