Insulation, Radiant and Vapor Barriers - Help - Insulate garage under livable space

I live in Houston, Texas and I have a home currently under contruction. There's a single car garage that is attached to the home via a porte cachere. Above the garage is an unfinished space (left that way by the builder) that I will finish later once I close on the house. Of course, I plan on insulating and cooling this space as part of that process. The garage itself will be finished by the builder with sheetrock and trim, however, will not be insulated. I plan on insulating the garage prior to sheetrocking for two reasons: 1.) to insulate the finished area above (installed in the ceiling below) and 2.) to provide some level of comfort within the garage since I plan on using this as a workshop. I have done a lot of research on installing the insulation, which unfortunately has left me more confused than when I started. My questions specifically would be...

1. Since I plan on using the standard batting type insulation (most likely with a kraft paper facing), to which side should the kraft paper face within the walls? I've read it should be to the inside of the room, but for hot humid climates that may be different. Houston seems to qualify in that regard.
2.) Should the kraft paper be installed against the floor above or facing the floor below when placed in the ceiling?
3.) If it faces the floor, that probably prevents me from stapling it, so how should I secure it in the ceiling?

I plan on doing this soon, (like tomorrow :wall: ) so hopefully someone can help me soon. I appreciate the assistance.

hgrays