Found this how to on the internets.
remove door panel
leave window up
remove latch rod
remove securing hardware (rivets/bolts) can't remember which
remove old handle
Install, reverse procedure.
You will need a rivet gun almost 100% sure and a good sharp drill bit to drill out the rivets that are already in there.
2000 Mustang GT Steeda build #48. Bolt ons, suspension, Novi 2000.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.