Students join a Nearpod presentation using a code. Go to nearpod.com and they enter the code and click join a lesson.
Here's a quick slideshow showing how students join Nearpod:
https://docs.google.com/presentation/d/10JhTQZpa9iVgHs52SjxBDj7c4i-oWrHzUcZ9tOKWLs4/preview