There are 2 Shootouts. You will be in one of them.
The shootout is 20 minutes long. In that 20 minutes you do as many laps as you see fit. After both shootouts have finished, I combine the results from both shootouts and the top 15 from the combined list go through to the race meeting itself.
I hope this hasn't come across as terse, I just wanted to clarify the situation for you. I think this is written in the rules anyway, but if you need clarity then the passage above should provide it. Please let me know if you're happy with the explanation as I don't want anyone to not know what is going on