The components of the rack bracket can be directly assembled, but when you install the assembled rack bracket on the wall or board, you need to drill holes in the wall/board and install the rack bracket with screws.
The 20X Heavy Duty Cast Iron L-shaped Wall Mounted Shelf Brackets are a great fit for spaces in need of robust support for decorative items, such as walls, shelves, or closets, where a traditional post-and-board system may not be sufficient for the weight and variety of items to be stored.