Select a place to install the recessed, porcelain soap dish. Make sure it is high enough on the wall to be convenient, and it if possible center it in the middle of two or four tiles.
Tape the template for the porcelain soap holder on the wall with painter's tape. Make sure the template is straight; use a level to make sure the lines on the template are plumb. If you don't have a template, see Tips.
Drill a hole in the middle of the template (or square/rectangle you drew) with an electric drill. Then insert the 4-inch diamond grinder into the hole and cut away the wall inside the lines of the template. Use light, even pressure to avoid cracking the tiles.
Position the recessed soap holder into the hole and make sure it fits. If the hole isn't quite big enough, trim away a little more but be careful not to trim too much or crack the tile.
Line the perimeter of the hole in the wall and line the back edges of the holder with adhesive silicone. Then quickly place the soap holder into the hole. The adhesive will make the holder stick to the tile or wall. Wipe away any excess adhesive before it dries.
Hold the soap dish in place with silver duct tape, and leave it in place until the adhesive dries.
Select a place to install the toilet paper holder. Make sure it is near the toilet and not too high or low on the wall.
Move the stud finder from left to right in the preferred area and locate the nearest stud, then mark it with a pen. Now use the stud finder to locate the center of the stud and mark that with the pen. You want the center of the toilet paper holder to line up with the center of the stud. If there is no stud in the area where you want to place the holder, skip this step.
Tape the template for the toilet paper holder on the wall with painter's tape. Make sure the template is straight; use a level to make sure the lines on the template are plumb. If you don't have a template, see Tips.
Drill a hole in the middle of the template (or square/rectangle you drew) with an electric drill. Then insert the keyhole saw into the hole and cut away the wall inside the lines of the template.
Position the toilet paper holder into the hole and make sure it fits. If the hole isn't quite big enough, trim away a little more but be careful not to trim too much.
Insert the screws through the mounting holes of the toilet paper holder and into the stud with an electric drill. If there is no stud, line the back edges of the holder with construction adhesive. Then quickly place the toilet paper holder into the hole. The adhesive will make the holder stick to the wall. Wipe away any excess adhesive before it dries. Tape the perimeter of the holder to the wall for several hours until the adhesive dries, then remove the tape.