There are ways and there are ways. This post shows a couple of ways to do it.
Shower is a walk-in, about 5' by 7'. Door is at a 45 degree angle.
Walk in to the shower and on the short wall to the immediate right are two supply valves, the lower one supplies the wall mounted handheld, the upper supplies an overhead 12" rainshower head.
Moving counterclockwise from that wall, the long wall on the right is on an exterior wall, nothing but tile.
The short back wall has a 2-shelf niche, about 36" wide and 30" tall. The lower niche space is 15" high, the shelf itself is 4" thick, the upper niche space is 11" high.
The last wall, the long wall to the left as you enter, has the wall-mounted hand-held. If I recall, the sliding bar is 40" tall.
Tile backer? I prefer cement board on the walls. Wonderboard or Durock. I used Wonderboard on these walls. The ceiling and niche is done in Hardie, as Hardie is less brittle so for me it's easier to cut into narrow strips to trim out the niche, and not as prone to snapping when installing full sheets overhead.