Somewhere in the tutorials located here

but there's no tutorials that explain how the actor touch by the enemy? in tutorials only the move, sounds, enemy movement are included.

Yes it does cover detection here

but how the enemy kill the actor?

You should try downloading a little crab scenario and look up how this problems are solved there.

may I know what page is it?

Thank You JerLennit and Gevater for helping me ^_^