So the video stated the way a law can become a bill. This law was formed in the minds of the people then sent to a congressional representative. In this case he created a Bill that stated that buses should stop at railroad crossings. He then sent it to Congress where a select group of individuals form a committee to review the bill and then vote on it. Here it can be killed but if it is passed it goes into a near never ending cycle.
This process starts in the House of Representatives where they argue over it and vote on it. If they vote no it dies if they vote yes it moves on to the Senate where the same process is repeated. Finally the bill gets on line for the president to sign. There he can say yes and it becomes a Law or he can veto it where it goes through committee and congress all over again with the possibility of editing or death.