You buy as many tickets as you can afford (this helps offset the cost of putting on the regatta) and if your number is drawn you simply walk up to the prize table and pick up what ever you want. Tip: visit the prize table and figure out your choices would be in order, this helps move things along faster. For example First choice would be a sub kit, but if someone else picked it first then you would take the radio set and so on. At last years regatta I picked a large stack of SCR back issues when my number was drawn.
Repeat the process on Sunday.
Best of luck to you if you go.
Put your heart into it, well done is better than well said... Ben Franklin