You can use both start and begin for an activity. "Begin" is more formal than "start":

I started playing the piano when I was 8 years old.

What time does the meeting start?

He's beginning to read more advanced books in English.

We left the park when it began to rain.

When you turn on a car or vehicle, use "start":

I had to call a mechanic because my car wouldn't start.

In general, begin is used for more formal and more abstract ideas:

Scientists are studying how life began on earth.

World War II began in 1939.

Rules to play Ultimate Frisbee

Score points with complete passes

A point is scored by completing a pass into the opponents end zone territory. Upon scoring a point, the possession of the disc changes to the team that was scored upon. The team in possession of the Frisbee will be trying to score and the other team will be trying to disrupt play and get possession of the Frisbee, so they may score.A point is scored when a player passes the Frisbee to another player who is standing in the end zone, and that player makes the catch successfully. At that point, play ends and the defending team will receive possession of the Frisbee.Substitutions may be made in the transition period after a point is scored and before the other team takes over possession of the disc.