that means without the complete harness, stock engine, stock engine ECU, and everything else, you would need to setup some sort of set of electronic switches to manually shift gears.
There are aftermarket transmission controllers out there - here is one
Transmission Controller, Transmission Computer, Stand-Alone Computer, Monster Transmission, 4l60e computer, 4l80e computer, 4r100 computer, 4r70w computer, 4l85e computer, 4l65e computer, aode computer, e4od computer, 4l60e controller, 4l80e controll
there are probably other options. it would not be very hard to make one with a an arduino but I don't know how.
Inputs are RPM, Throttle position, and mph.
Outputs are power or ground to two solenoids for shifting and a third control for torque converter lockup.