ここで遊んではいけない。

here (place physically close to the speaker, place pointed by the speaker while explaining); this place; these last (followed by a duration noun and a past sentence: time period before the present time of the speaker); these next ... (followed by a duration noun and a non past sentence: time period after the present time of the speaker); the next ...

indicates location of action; at; in; indicates time of action; indicates means of action; cause of effect; by; and then; so; indicates continuing action; indicates certainty, emphasis, etc.

to play; to enjoy oneself; to have a good time; to mess about (with alcohol, gambling, philandery, etc.); to be idle; to do nothing; to be unused; to go to (for pleasure or for study); to intentionally throw a ball to lower the batter's concentration

if ... then; when; and; why don't you...?; the more (one does something); because; since