To ask a question in the present continuous tense, we put am/is/are before the subject.
am/is/are + subject + -ing
Study these examples
I am dreaming. → Am I dreaming?
You are cooking. → Are you cooking?
He is leaving. → Is he leaving?
If there is a question word (where, what, how, who etc.), we put it at the beginning of the sentence.
What are you cooking?
Why is he leaving?
To give a short answer, we only keep the auxiliary verb am/is/are (+ not) and do not repeat the main verb.
Am I working hard now? Yes, I am.
Are you going home? Yes, you are.
Is he leaving? No, he isn't.
Is she wearing a hat? Yes, she is.
Is it snowing outside? No, it isn't.
Are we having fun? Yes, we are.
Are they having lunch? No, they aren't.
In "yes" answers, we do not shorten the auxiliary verb: Yes, I am. Yes, you are. Yes, he is.
In "no" answers, it is better to shorten it: No, I'm not. No, you aren't. No, he isn't.