Chris,
Tips as follows:
1. Make sure you pre join the TCA if you haven't done so already.
http://www.trailquest.co.uk/members/ Associate membership is FOC but they'll give you an online membership card to print and take along. This saves loads of hassle at registration.
2. Get there in plenty of time before the start. It's a bit chaotic with everyone at registration desk so get in the queue marked 'Unpaid Pre-entries', pay, collect timing chip, race number and control descriptions.
3. Map boards are a good idea. There are usually some at registration for sale (fairly cheap DIY ones that won't break the bank).
4. There will be a map of the race area near registration for you to study. The control locations won't be marked on it but it will show you the permitted tracks and the terrain.
5. Familiarise yourself with the various track markings. There are ones showing major and minor tracks, rough/boggy ground and OUT OF BOUNDS. Do not pick a route that uses anything other than a permitted track. You will be disqualified.
6. When you're ready, go to the start line. There will be a device to CLEAR your timing chip. When it's your turn you'll be asked to enter a box where you'll be given your map with controls marked on it and 60 seconds to study it before you start. You'll then insert your chip into the start device and you're off.
7. When you reach a control, dib your chip in and make sure it beeps.
8. Make sure you're back on time. You'll lose points for every minute late back and, if you're very late back (30 mins) you'll lose all points.
See you Sat. Good luck!