It's basically a monorail that loops around downtown.
There is a coffee/pastry type of place about 1 1/2 blocks away that you can see if you stand on the corner of the hotel's driveway (hard to explain, but walk towards the "shops of the downtown streets" and you can't miss it. There's also a starbucks a few more blocks away if you're into that.
Re: Hyatt Miami - distance to port and to Bayside Marketplac
I'm not sure of the Sheraton's loction (although i've heard it's a nice hotel).
This map of the MetroMover is pretty good and i'm sure you can figure it out based upon the address of the Sheraton. You could also just call the Sheraton and ask them how close they are to the MetroMover.