Question

For science, we have a fire extinguisher project. We have to make our own fire extinguisher with a limited budget, and be able to extinguish small tea candles in a metal box. I'm fine with the design, basic idea.

I am stuck on how much vinegar and baking soda is needed to produce enough gas, which is figured out by stoichiometry. I got the measurements of the box, but I have no idea if I use the measurements and apply it to some kind of formula. What steps do I need to make stoichiometric equations to find the amount of reactants needed to extinguish the fires?