Firstly you out to be in a tweed & shirt & tie. I's also pop your noseband up a hole (overall picture goes a long way)
Most ridden classes consist of walking trotting & cantering as a group, changing the rein in trot & doing the same.
Then all line up either in any order or in a prelim order (whichever judge chooses)
A normal individual show goes roughly:
Walk up to & stand by judge side on to the line up & facing the way you will begine (normally right rein). Walk away from judge for a few strides, then ask for trot. trot round to the right, and across the diagonal onto other rein, trot 1 side then canter, change rein again across centre in trot, picking up canter as you come off the diagonal. Ask for an extended canter along the long side - i prefer on opposite side to the line up, not behind it.. Then pull up to a trot then square halt & salute.
Most judges will look for an outline the reflects ponies age/level so a novice pony won't be expected to have an accomplished outline but something resembling working properly is desired from any ridden show animal
Classes you could do? Coloured, cob, family pony, utility pony, working hunter?
hope that helps