The scrotum is created with rotational flaps tailored from the both labia majora.
Scrotoplasty is performed with metoidioplasty or phalloplasty at the same stage, but testicular implants are placed later. I have never performed scrotoplasty and testicular implantation at the same time. These surgeries require at least two separate steps spaced 3 months or more apart.
Scrotoplasty can be done as a separate operation in some cases. Sometimes the labia majora have already removed or tissues of them are not enough. In such cases can be used any different rotational flaps from the inguinal (groin) or inner thigh areas.