Close. The first sentence is good. Please lead me to the manager --> makes sense. I would say, "Please take me to the manager" He is no singer --> Is okay (and more fun), but could also be "He is not a good singer". Tom always tries to be a good father to his children. --> excellent. Before coming of guests, I decided to do the room. --> "Before the guests arrive, I decided to clean the room". (I think that is what you mean. I hope that is helpful.