Use a plastic opening tool to pry the edge of the home button ribbon cable up from the display assembly.

Start on the right, at the area of the ribbon cable between the gold contact points, and work to the left.

Going left to right may rip your ribbon cable as the contacts are well adhered to the front panel.

Prying directly at one gold contact point or the other may break its soldering and pop it off the ribbon cable.

If you have trouble sliding the plastic opening tool under the contact points, flip the tool over and gently push against the right side of the contacts to loosen the adhesive, then try again.