In the bottom of each letterpress block, pre-drill a hole for a hook. It can be tricky to gauge how deep you've drilled, so put a piece of tape around the drill bit to indicate where you should stop.
Screw the hooks into the bottom of the blocks by hand. Longer hooks work well for a project like this because the ends extend below the backer board, which you'll add next.
Apply construction glue to the back of the blocks, space them out evenly across a backer board, and press down firmly. When adhesive dries, attach a wall hanger that will hold the project securely.
