Remove the home button bracket.

Be careful when you remove the home button bracket. There may be a small plastic washer wedged between the bracket and the button. If there is, be sure to retain this washer for reinstallation.

During reassembly, after installing the home button, you'll need to glue this bracket into place to secure it.

Scrape off as much of the old adhesive residue as you can, then clean it with acetone or high concentration (>90%) isopropyl alcohol.

Secure the bracket with E6000 glue, superglue, or high-strength double-sided tape. Make sure the bracket is aligned correctly before allowing your adhesive to cure, or the home button will not click when pressed.