Babe - when you get it - READ
the instructions that come with it before
trying to use it - and make sure you put them away in a place where you can find them in the future.
Although dehydrators all do to same thing - different dehydrators are made differently - timing may be different, some have variable temps, some have variable vents affecting air flow/temp/time ... you need to read your manual to get a basic understanding of how to use your particular dehydrator.
While you're waiting for it to get there, and before you go out and buy a book - you might want to read some reliable info for free ... The National Center For Home Food Preservation
has a section on Drying foods