I'm new user of C4D, I just start learning a few days ago.
I have question.
In the attached picture, and what is that 2 lines beside the object or model I'm working? can i remove that? and how to remove that?
The lines indicate the part of your viewport that will render when you render to picture viewer. If you want to get rid of them you can go to the Options menu on top of the viewport, select Configure (or Configure All), and then in the View tab, uncheck "Safe Frames".