Forum:B.E.S Tetran's effect (question)

Me and my bro ran into a disagreement about this guys effect... When you summon him you put 3 counters right, cool. And the card says if this card does battle you remove a counter at the end of the damage step *also* by removing a counter from this card destroy 1 spell or trap on the field. Soo here's our confusion: after the card does battle is that when a spell or trap can be selected and destroyed? Or does this have to be done manually?.. Or both??