I'm no expert on German, but that looks fine to me. All the words are correct but I'm not entirely sure about the cases/case endings. It looks pretty good to me though. Sorry if I couldn't be a better help :)
We have to say ''please'' and ''thank you'' because we are requesting another person then speak please, and anyone help u then we are saying thank you.
It is also a good behaviour or manner of human being.
Thanks♥♥