Locate the studs in the walls of your closet using the stud finder to help determine the layout of your shelving. Transfer any planned layouts or ideas to their spaces on the wall by writing lightly in pencil what types of shelving will go in each section. Plan each area of shelving so that the shelf will have support on at least two wall studs. Arrange the design to include space for heavier, longer shelves to have additional support on three or more studs.
Measure the distance between the center of each stud for the first shelving area. Turn the first shelf board upside down and arrange the brackets evenly on the underside of the shelf, keeping them the same distance apart as the wall studs. Predrill the bracket holes and attach the brackets to the shelf using wood screws, being careful not to let the screws poke through the surface of the shelf.
Position the shelf on the wall in the desired location, with the bracket holes over the wall stud markings. Set the carpenter's level on top of the shelf, and adjust the shelf until it reads completely level. Predrill the bracket holes in the wall and attach the shelf with wood screws.
Repeat the process for the next shelf board, leaving enough space to account for the brackets necessary for the shelf above and below. Vary the shelving spacing and size of the boards for the different types of clothing to be stored in each area.