These three shelves come preassembled—yay!  They were well packaged and they are very solid and sturdy.  As you can see from my photos, they come with REAL installation instructions, big solid screws/anchors, and even a tiny level.  Take note from the photo on Wayfair that they each vary a tiny bit in the depth.  That’s fine for my purpose, but it may matter if you you are looking for three shelves all exactly the same depth.  I can’t wait for my son to install them!