Next you will need to remove the display to be able to gain access to the home button flex cable assembly.

Use a heat gun, hair dryer, or an iOpener to heat the adhesive that is holding the screen in place. Heat around the outer edges of the display in a constant moving fashion.

If using a heat gun make sure to not overheat the display. Make sure you keep the heat gun moving and do not heat in one area for to long. Doing so can cause damage to the display.

Also try not to stick your separating tools to far in the device especially at the top and bottom of the display. Doing so could cause you to cut through a flex cable for the digitizer/LCD at the top of screen or the home button flex cable on the bottom of the display.