Gypsum wall board is another name for drywall. Drywall is a panel made of gypsum plaster pressed between two thick sheets of paper. It's used to make interior walls or ceilings. It is located everywhere in your house, and is there as a layer over wall studs.
Flooring (Carpet, Hardwood, Tile, etc.)
In the picture i am standing on tile. The significance of flooring is so that you do not walk on plywood or concrete slab, unless you want to then go ahead. Flooring can consist of many things such as tile, hardwood, and laminate. It is located everywhere you walk in your house.
Baseboards are a narrow wooden board running along the base of an interior wall. Finish carpentry is a wooden boarder that surrounds the floor, ceiling, and doors of a house. In my opinion it is only there for looks and design.