https://en.wikipedia.org/wiki/Manned_Maneuvering_Unit

There were 24 nozzle thrusters placed at different locations on the MMU. To operate the propulsion system, the astronaut used their fingertips to manipulate hand controllers at the ends of the MMU's two arms. The right controller produced rotational acceleration for roll, pitch, and yaw. The left controller produced translational acceleration for moving forward-back, up-down, and left-right. Coordination of the two controllers produced intricate movements in the unit. Once a desired orientation was achieved, the astronaut could engage an automatic attitude-hold function that maintained the inertial attitude of the unit in flight. This freed both hands for work.

Interesting but unrelated fact about Mccandless: His grandfather and father won the Medal of Honor in WW1 and WW2, respectively. They, and Bruce, served in the Navy.