How do you install grab bars in a shower?

What I do is drill a 1/4" hole in the tile (use the bar as a template, mark your holes with a pencil) with a masonry bit. This can be difficult depending on the type of tile you have. You may have to buy a diamond core bit if a masonry bit does not drill it. Then use a smaller drill bit to drill into the wall at each hole. This bit needs to be small enough to be a pilot hole for your screws as if you were drilling a pilot hole into wood. Keep track of the holes that hit wood with this bit. You will not need to use mollys in these holes. The other holes drill through the Sheetrock with a 1/4" bit and use a hammer to tap 1/4" plastic mollys into the tile. You can now use the screws that came with the bars to secure the bars to the wall. Good luck!