Better to take a van but if you have to ride get a mate to take their car.
Gives you the chance to take a packed lunch, fuel (they will crucify you at the circuit), spare kit/clothes etc.
don't worry too much though as the most important thing is to have fun.
A track day is the best way to get to know your bike. You won't be the fastest in your group but I doubt you'll be the slowest either.
Just do your own thing.
They'll have instructors there and it's worth having one show you around.
Luckily Silverstone is so big you're unlikely to get lapped by faster riders or held up by the slow ones.
The only advice I will give is to remove your mirrors and to make sure your tyres aren't squared off.
Oh and ease into it. Learn the track, get the lines right and then increase the speed.
Have a great time.
