Hi,
Can you explain a bit more about what you are trying to achieve? there is many forms of implementation for this types of game and the context is very important to give valid advices.
Typically tho, this is very straighforward, you simply fire a global event like "SIMON SAYS / RUN" or "SIMON SAYS / STOP" and any player or NPC can watch for these events either by reacting to them or show something on screen to express what Simon Just said.
Then, one seconds from the call, you verify that each players is actually doing what simon said, so each player would have built in all the different possible things Simon could say and would maintain flags of what they do currently.
bye,
Jean