a round consists of shooting a set number of arrows at a set distance (or distances) onto a defined size target face(the piece of paper).
As an example, a Windsor round consists of 9 dozen arrows shot at three distances, 60, 50 and 40 yds. At each distance you shoot 3 dozen arrows.
There are rounds shot at longer and shorter distances and also rounds where more or fewer arrows are shot.
There is a list of rounds on the webpage linked to below.
http://davidhannibal.co.uk/archery_rounds.htm
You do not need to be in a competition to shoot a round.
As far as Handicaps & classifications go.
Each score you submit to your club records officer will count towards your handicap, the score will be cross referenced against the round you shot on a secret
GNAS table. Your handicap is determined by the average of your three best handicap round scores (regardless of the round shot).
Your classification is linked to this, but is determined by the scores you have shot in each round and the rounds you have shot. You will find that some of the higher classifications are not available on all rounds. As an example of this, the highest classification that can be attained by a Gentleman shooting a Windsor is second class. To attain First Class status I need to progress to longer rounds (such as an Albion).
Although progression through the classification ranks is not possible with some of the shorter rounds, handicap improvement is, and often people will shoot shorter rounds just to boost their handicap - though I'm not entirely sure why.
T.