From the Super Mario Wiki
Archery (Team) is a Shooting Event that appears exclusively in the Nintendo 3DS version of Mario & Sonic at the London 2012 Olympic Games. The aim of the event is to score the most points over the four ends as a team. The starting record for this event is 37pt(s). This event does not appear in the game's story mode.
In this event, the player competes as the four characters in the Heroes group and plays against three teams of blue, yellow and green Shy Guys. Each end has a different wind speed and is shot by a different character. The first end has no wind and is shot by Mario, the second has 2mph winds and is shot by Sonic, the third is shot by Luigi and has 4mph wind strength and the fourth is shot by Tails and has 6mph wind speeds. On the ends with winds, a direction is also given, however this varies each time the event is played and may also change while the player is aiming. Landing an arrow in either of the centermost rings of the gold will score ten points and are accompanied by a sparkle effect, wit each ring going outwards receiving one fewer point each time, with no points being awarded for missing the target or the boss entirely. If the arrow splits a line, the higher score value is given. The player's total score, as well as the score of each archer is kept throughout the round and their placing is updated when they overtake the other teams.
1) Shoot: Hold and release the R Button.