You are correct that when you
say your callsign you use either november or the make. Regardless of how you say it, the actual callsign of an (American registered) aircraft starts with an "N". The controller wants you to
login to PilotEdge with a correct call sign. In your case that is N180D.
So, your callsign is N180D. To login to PilotEdge make sure you type in the callsign box N180D. To express it on the radio, you can say either "november one eight zero delta" or "Piper one eight zero delta".
Regarding responding to "How do you copy?" just answer

. You can use normal English on the radio in order to communicate. Commonly used phrases are "loud and clear", or
5 by 5. Note, a controller asking "How do you copy?" probably indicates that they've been trying to contact you for awhile. It's possible that you've missed some calls and he wants to get your attention and make sure you haven't had a communication failure.