Question about Lifegaurd duty?

[shio]

I had this game for about a year now but the computer i had wasn't good enough to play it, but I recently got a better computer so it works now! But since it didn't work on my old one i didn't think much of the game so I lost the manual and map thingy. So now i am doing a War Patrol for practice but it says to do Lifeguard duty but i don't know what to do. So how do i do it?