Wipe down the wall area where you will install the shelf with a damp rag to remove any dirt and dust. Locate the studs within the wall with a stud finder, and mark their locations on the wall with a pencil.
Lift the shelf's mounting bracket or hanger board and set it against the wall. This piece of wood will support most of the weight of the shelf. It will feature one side with a sharp angle cut into it; this angle must face upward to properly support the weight of the shelf.
Set the bracket in place against the wall at the height where you want to install the shelf. Use a level to make sure the bracket is completely straight.
Screw the mounting bracket into the wall with drywall screws. Attach the bracket to each stud it crosses for the strongest hold. Install additional screws between the studs if necessary to secure the bracket in place.
Slide the main shelf down over the mounting bracket until it sits tightly against the wall and firmly against the mounting bracket. Nail the shelf to the bracket with finishing nails to secure the shelf in place.