Conjugating "~고 있다"
Hi,
How do I conjugate the "~고 있다"? I'm asking since I know 있다 in itself can play different roles (meaning either "to have" or “to be in/at a location”) and these apparently conjugates differently. Now neither of these seem to fit into the description of how "~고 있다" work, so how should I conjugate it? Like a verb?
"I am studying." (basic form) is 저는 공부하고 있는다?
Thanks, Lukas