There is some guidance in the small & medium places of entertainment guide which seems most appropriate in this case however much of this depends on how many people are employed, the use of fire marshals, etc. and would need a FRA to support and underline the procedures. I'd think this would take about 20-30 seconds 'trolley dolly style' and there's no need for PowerPoint. Extract below.
At the start of the event or function you should
notify all those present about:
• the smoking policy;
• the emergency warning signal;
• who is supervising and how to identify them;
• location of exits and escape routes;
• taking only valuables immediately to hand but
not to go to collect other belongings;
• the location of muster points; and
• what will happen after that (e.g. re-entry to
the building).