FRC stands for First Robotics Competition. It is a competition where a group of students from grades 9th-12th build a robot and compete at competitions.
FIRST is a "sport of the mind". It involves programming, business, CAD design, art, and building. It is an experince that teamwork, having fun, and being safe are among the top priorities. These students work alongside mentors and peers to get the job done.
Below is a video from FIRST's youtube channel describing what FRC involves.
This is a video of how the AT Home challenges were done for 2021.
This is a video of a competition. This is a random one in Escanaba, MI in 2018, but is shows how competitions usually are.