Okay, might be stupid question but grandmaster sprinkler help

This is probably so obvious but I’ve only used sprinklers to make big fruits….

I’ve seen a Rbh Ele that I’ve been told can hit cap with large and small toy or grandmaster, with small and medium toy.

How does the grandmaster work? Is it just placed in the garden makes it work or do I need to use a pet lead to keep the Ele near it whilst it’s running?