Glue the four smaller pieces of glue together. I just used normal PDA glue.
I also used a nail gun to make sure the frame would stay, and used a hammer to make sure the nails were well grounded. The nails are almost invisible to the eye.
(However, I didn't fully think things through, because I still want to put my speakers in, which is not impossible at this stage, but is definitely harder so I recommend you do step # _ before you do this one.)