Personal experience overrides everything here. After a try a conversion may be attempted by place kick or drop kick. If the ball passes over the bar and between the goal posts the conversion is successful and results in a further 2 points. Players may not be tackled without the ball. Play only stops when a try is scored, or the ball goes out of play, or an infringement occurs.
Infringements result in a penalty, free kick, or scrum.
In a scrum the opposing forwards bind together in a unit and push against the other forwards, trying to win the ball with their feet. Substitutions are only allowed in case of injury and there is no separate offensive and defensive unit. The names of the positions vary quite a bit between the various rugby playing nations. The following is based on the numbering scheme for player's jerseys currently laid down by the I.R.F.B. for International Matches. It is commonly, though not universally, adopted by other teams.