Heyy.....help please!!?

can anyone please help me..i have just started baking business from home...n have rented a stall in an exhibition...m quite confused as to what all i should keep in the menu and how much should i keep..i was thinking on mousse, tarts,brownies,chocs,cupcakes n pastries too but which flavor and in how much quantity should i keep is confusing me...please help me ...its a 1 day exhibition!