Agree with what Simon said and some additional comments as follows:
Arrive at ground in plenty of time to book in and go on zero range etc. I normally allow an hour and half.
Am Session starts 09:00 with briefing say 08:45. PM session starts at 13:00 or as soon as possible after that time.
Remember the clock only starts when you put your eye to the scope, so get settled, loaded etc for first shot.
Don't rush, take your time as 2 mins is plenty.
Most of all .... ENJOY!