An example bracket unit to control installation of an electronic module is provided herein. The bracket unit includes a bracket body, a bracket plate, and a fastener. The bracket plate includes a receiving member and an alignment indicator. The receiving member to engage with a rail unit and move between an equilibrium position and a displaced position based on a movement of the rail unit. The alignment indicator connected to the receiving member, such that movement of the alignment indicator corresponds to the movement of the receiving member. The fastener to slideably connect the bracket plate and the bracket body together.