Ok, first why Anglesey? It's a good circuit and relatively safe, but it is tight and technical. Bedford is an ideal starter, open and plenty of room to get offline and out of shape.
It's a tyre wrecker, so keep and eye on the n/s front overheating or wearing - rotate if necessary at lunch.
Take some basic tools, tyre pressure gauge, pump and some oil.
Put on a novice sticker
Listen at the briefing, don't be afraid to ask
Book instruction
Be aware of the car. If the tyres feel greasy, come in. If the brakes feel wooly, come in. If something's sounding or feeling wrong, come in.
Enjoy.