make a leaflet of dos and donts to tell schol students what to do when
playing outside
Как можно написать?

   Do NOT talk to the strangers when you play outside. 
Do NOT buy any food or drinks.
Do NOT scream or shout.
Do NOT turn on the music on your mobile or notebook too loud.

Ask other boys and girls to join you, if you see that somebody is not invited.
If there is a couch or another adult with you, listen to his/her attentively. 
If a stranger is asking you or somebody from your group to go with him/her somewhere or to have a ride with him/her, tell about it immidiately to the couch/teacher or call your parents.