I'm trying to figure out how to frame and build both a small niche that will be used for a phone and a larger recessed area that could hold shelves (e.g., 4-5 feet long).

It seems the options for the larger built-in shelving include framing the wall to put in a ready-made unit or framing and finishing it in drywall and then adding shelves somehow. At a minimum I want to frame this so that I can cut the wall open later and install the shelving.

For the smaller niche, it seems that the bottom part needs to be wood or some other hard surface but I don't have a mental picture of how this gets put together.

Any pictures of in-progress or completed niches or recesses would be appreciated, or other advice!