You get 5 lives and 5 minutes (hence the 5v5)

The idea is to go around the board hitting the segments 1-20 then, finish on bull

So start out you begin on 1, you throw your dart if you hit S1 then move to 2, if you hit D1 then move to 3 as you are moving 2 up, if you hit T1 then move to 4..

If you miss all 3 darts a 1 you will loose a life.

So now lets say we hit T1 first dart, i now move to 4, i hit T4 with my second dart im now on 7 with my 3rd dart and i miss the 7 completely, In this instance i loose a life and when i come back to throw will move down to 6.
So if you miss what you are after you move down 1 number, even if you have move 2-3 numbers up from your last throw.

In theory a beginner player will loose the lifes first and not be caught by the 5 minutes of time, but the better players will hopefully get round to 20 in with lifes to spare.

When you get to 20's you then get locked in that zone and dont move backwards from here. 
Previous go (3 darts in hand) im on 19's i hit T19 first dart, i move to 20's i dont advance to bull !! but i have to hit my 20 with my second or third dart to lock in the 20's.

Once you are locked in you can only move onto the bull by hitting shanghai (S20, T20, D20) you can hit S20,T20 or T20, S20 up to you but 3rd dart must be the D20
If you miss with your first dart at the 20's (say you go in the 5) to save a life you must hit the bull, if you dont hit the bull you will then loose that life, but you are locked in the 20's at this point so your next 3 darts will be at trying get shanghai to get to the bull.

Once you have hit shanghai and moved to the bull, in theory your time will be catching up with you and possibly low on life's. For an instance here i have hit Shanghai and now have 40seconds on the clock but only 2 life's left BUT im on the bull.

My next throw will be for bull, you dont have to hit all 3 in the bull just one dart to win, so next 3 darts i thrown and dont hit the bull i loose a life , down to one life and now with just 28 seconds on the clock but then i hit the bull with my next dart so i win and my time is say 23 seconds.