Set out the pieces of your trinity shelf. There will be four long poles, one for each side of the shelf, and three to five shelves that fit between each pole.
Attach the bottom shelf to the poles. Place each pole against the corner of the shelf and use the screws to tighten the shelf and poles together. Repeat the process with each shelf on the trinity wall shelf.
Locate the studs in your wall with the stud finder and mark their location with the pencil. You’ll need to brace the shelf against the length of two wall studs.
Drill one hole into each wall stud about 3 to 4 inches shorter than the top of the trinity shelf. Screw the brackets into the wall with the screwdriver. Drill two more holes into the wall studs spaced evenly 5 to 6 inches from the other studs. Attach brackets to those holes with the screwdriver.
Push the shelf against the wall brackets. Place a screw into the hole to attach the shelf to the bracket and tighten it with the screwdriver.