Draw a map of the school grounds and plan out where each stall should be positioned.
It is best to confine your fete to a limited area rather than spreading it throughout the entire grounds. This way you can keep your attendees circulating around your stalls. Spreading out too much can lose customers. Choose an area that is flat with easy access for prams / wheel chairs.
Stalls may need power, especially if the event is to carry on into the evening and lighting is required.
If the carnival company chosen is large they will supply their own power for their rides, lighting and music which is a cost saving to the school.