Thanks Carolina Speed.
Rugby Union Basics are -
Scoring - 5 points for a Try(Touchdown) 2 points for the resulting kick(Extra Point). Ball must be touched down past the line, can't just run through the end line.
General Play -
Ball must be thrown back, no forward passes
When a player goes to ground, opposition may try to get the ball back, once they stay on their feet. Player with the ball must release it back to his team, he can't just lay on the ground and hold on for dear life.. So basically when you make a run, it's important to have team mates that hold off opposition and let you place the ball for the scrum half(player who generally picks the ball up and passes it first, starting another phase of attack)
It can be confusing in some aspects. Like anything, the more you watch, the more you will pick up. Rugby Union is all about international games, as opposed to club matches like soccer for e.g