Lead installers work in construction. They work under the supervision of an install manager and they coordinate the work of an install team. They work on residential constructions, carrying out projects of various sizes from remodeling to home additions. They monitor the workers' performance and report on the progress of the work to the construction manager.
As construction staff tends to be, lead installers are skilled tradesmen trained in various phases of a construction job such as demolition and pre-construction, framing, plumbing, electrical wiring, installing tiles, painting, and the list goes on. They assign tasks to installers and manages the schedule of sub-contractors and helpers, filling in the role of the leader on-site.
A high school diploma should do it, as far as formal education goes, book-smart is not what a good lead installer is expected to be. What makes or breaks a pro is the amount of experience gained in construction work.