You need to click Img tag in the editor panel, ctrl+c the link where you uploaded your image (tinypic for example) and ctrl+v the link in the editor.
I suggest you to start looking at the Alvaro tutorial if you have just started... it helps
Anyway Buddh Circuit is currently in progress for the official MRO (if not already completed, ask Vany)
but you can share your own version, let see what you have done

Alvaro-Vany are usually the right guys to ask for some help