It`s wrong to put "do" as well as the question mark (?)
I mean that this kind of sentences are known as Indirect Question.
As you add an indirect clause at the beginning you do not end asking.
I mean the following:
How old are you?
I would like to know how old you are
I would like to know how old
This is the whole help that I can give you, since it is difficult to explain it by writing, you`d better ask a teacher. Considerate my advice, nice to meet you and good luck...
Student or Learner