Within the 192 National Ignition Facility (NIF) beamlines, there are more than 7000 large (40×40 cm) optical components, including laser glass, mirrors, lenses, and polarizers. These optics are held in large optomechanical assemblies called line-replaceable units (LRUs). Each LRU has strict specifications with respect to cleanliness, alignment, and wavefront so that once activated, each NIF beamline will meet its performance requirements. NIF LRUs are assembled, tested, and refurbished in on-site cleanroom facilities. The assembled LRUs weigh up to 1800 kg, and are about the size of a phone booth. They are transported in portable clean "canisters" and inserted into the NIF beampath using robotic transporters. This plug-and-play design allows LRUs to be easily removed from the beampath for maintenance or upgrades. Commissioning of the first NIF quad, an activity known as NIF Early Light (NEL), has validated LRU designs and architecture, as well as demonstrated that LRUs can be assembled and installed as designed. Furthermore, it has served to develop key processes and tools forming the foundation for NIF's long-term LRU production and maintenance strategy. As we look forward to building out the rest of NIF, the challenge lies in scaling up the production rate while maintaining quality, implementing process improvements, and fully leveraging the learning and experience gained from NEL. This work provides an overview of the facilities, equipment, and processes used to assemble and install LRUs in NIF.