5. Pull a measurement from the floor of your garage to the ceiling next to the garage door opening. Cut two 2’’ x 6’’ pieces of lumber, and attach to the face of the wall running from the edge of your garage door jambs to the ceiling of your garage. This lumber will be used to attach your garage door track, and a portion of your assembly.
6. Next, pull a measurement between the 2’’x 6’’ lumber that you just attached to the face of the garage wall. Now, cut a 2’’x 6’’ piece of lumber to that measurement. Attach lumber to the face of the garage wall to the edge of the garage door header
7. Last, pull a measurement from the top of the 2’’ x 6’’ piece of lumber that you just installed to the ceiling of the garage. Cut a 2’’x 6’’ piece of lumber, and nail to the face of wall exactly in the center of the garage header. This piece of lumber will be used to attach the center bracket of your garage door spring assembly.
Click on the image below for clear detail and drawing.