I need to put a 15 amp outlet that has its own breaker in my kitchen above the cabinets or in cab over oven. This is for a microwave oven. Thanks in advance for any help!

What exactly is your question?

Do you need to know each step of installing a 15 amp circuit to an outlet for a microwave above a range?

First, I would install a 20 amp circuit using #12 wire.

What is your level of expertise? Do you have knowledge of working with tools, electrical materials, and working in panelboards?

What type of cable is in your home? Romex? MC? BX? Conduit?

What type of construction? Wood studded framing? Masonry? Balloon construction?

Will the outlet be on an exterior wall that is insulated?

Can the exterior wall be accessed with a drill from either the basement or the attic?

What is the wall finish? Drywall? Plaster with wood or metal lathe?

Where is the panel located? Can it be accessed to install a new cable into?

My point is there is no one answer for a general question such as yours. Really need to know as much detail and specifics to provide a meaningful answer. I don't mean to be a smarta**, but there are too many variables to consider.