Rugby is governed by laws, not rules. The laws of the game are designed to produce an entertaining and free-flowing contest for possession in an attempt to score the most points.
The laws of rugby are constantly evolving and are the same all over the world, wherever the game is played. In general, the laws governing play are straightforward about what’s allowed, but three crucial parts can be somewhat confusing: the tackle situation, advantage, and offsides:
In a nutshell, when a tackle is made in rugby the requirements are that the tackler releases the tackled player, who then releases the ball so that players who are on their feet can use it.
Advantage simply means that when one team makes an error the other team can try to capitalize on it, instead of the referee immediately stopping the action. If the players can’t capitalize on the error, play restarts where the original mistake took place.
Specific offsides laws exist for different phases of play, but essentially players can’t be involved if they’re in front of a teammate who last played the ball or are behind the ball when the opposition has it.