https://www.hopkinsmedicine.org/center-transgender-health/services-appointments/faq/phalloplasty
More info than you want. They peel skin off, usually your arm, roll it like a jelly roll, and reroute your God given plumbing.
They list an astounding number of possible complications. Number 1 for me is they expect nerve regeneration, and warn that some or all nerves might not grow back in the surgically created skin tube that approximates a penis.