It is a requirement to display a sign at each entry that includes information on the maximum number of people that can be present in the space at a single time, rounded down to the nearest whole number.
There are lots of poster available. When placing posters, think about your audience and the activity, e.g. posters about how to wash your hands should be above the sink in the bathroom, posters about using hand sanitiser should be near where the hand sanitiser is available, posters should reflect the age of the audience.
The Scouts Victoria editable sign to indicate room capacity can be accessed here.
A range of posters is available from Business Victoria here