It depends on the exact car, transmission and what is being replaced. A mechanical replacement using the original supported controller may need different checks from installing a used or new mechatronic/TCU. Programming, coding, immobiliser/security authorisation, clutch/shift adaptation and fluid setup are distinct operations; not every application requires all of them.
Before fitting, determine the approved replacement procedure for the VIN and the supplied controller/hardware. Check whether the original controller can be reused, whether a module must be commissioned or calibrated and which adaptations or learning drive cycles are specified. Record any fault codes and verify fluid level using the correct temperature-based method where prescribed.
A gearbox that bolts into place is not thereby electrically configured or ready for road use.