This person moderates the participants, explains tasks and looks at the timing.
You have a good understanding of the briefing. If something is not clear: ask.
Take a look at the workshop script. Go through the program in detail (possibly with a dress rehearsal) so that you are saddle-fast with the instructions.
Talk to the customer before the intro. Who is responsible for what?
Get a good overview of the participants. The champ has a list of participants, which he likes to share with you.
Greet the participants as they arrive.
Please take the participants to the auditorium.
Play the daily hit.
Introduce yourself, the management team, the customer and briefly explain who BrainStore is.
Give the word to the customer as a greeting.
Take over again from the customer and start the workshop.
Invite others from the leadership team to co-host. But only if someone wants to :-). Too many moderators can confuse participants.
Announce the number of ideas from the amassing menu from time to time.
Adapt the program if necessary. You are responsible for good content, keeping the time and happy participants.