I just wanted to know how to add a new tab from my sheet?
I am able to create the tab but I am not able to see the source that I also added to my google sheet. So the question is how do I see or add the source correctly.
Do you mean the source sheet? Have you clicked on the reload button to get the latest version of the sheet? Is your screen size big enough and not possibly hidden below the bottom edge of your screen?
Yes. I reloaded and logged out and back in.
Is there data or at least headings in the sheet or is it completely empty?
Empty sheets are ignored. Now that you added a heading, try reloading the sheet.