Keep in mind as well, at least at this point in the game, Dimension is more or less compositing software. The assets need to be created in other programs.
This may or may not change, but as of right now, how I'm reading it, that's how the program is. So the objects that the logo/design are going on, have to be already be available and can't be created on the fly within Dimension itself.
If you are really wanting to do 3D mockups, probably looking for 3D modeling software with builtin compositing abilities. Until Dimensions can have modeling abilities (or they have pre-done assets that would have you covered for your needs (if they don't already).