Here are the abbreviated instructions for building my DIY floating wood shelf, for detailed instructions, please visit my blog at the link at the bottom of this post.
First, I used a stud finder to locate and mark the studs in the wall.
Next, I cut the boards that will be attached to the wall in the back and on the sides.
I then began attached the boards. I used a level to ensure the board was straight, and then I used brad nails to hold the board in place while I drilled screws into the boards over the studs.