For the HL-LHC upgrade the current ATLAS Inner Detector is replaced by an all-silicon system. The pixel detector will consist of three different subsystems with different mechanical support structures, resulting in an actively instrumented area of about 13 m^2. Prototypes of all flavours of support structures were loaded with pixel modules based on the RD53A readout chip. The different loading techniques, used in the different loading sites for the different support structures, are illustrated and discussed. The techniques range from being based on high precision positioned jig tools to multi-functional pick-and-place head on a robotic gantry.