If there's a specific line number you want to navigate to, say line 12, you can do :12 and it takes you there. If you want to navigate to a line that is relative to your current position you can do something like :-12 or :+12 to navigate there.

To debug in Emacs we can use (edebug-defun) to debug a function. Put the point inside a function definition and run this command then run the function normally to enter debug mode.