Geography coursework

Hi, I need help on how to structure the background theory part of my context for my nea. My teacher cannot help as he is assessing and i'm really confused on how to and where to find references (I've been told I need 7) that are effective for a level - the effect if vegetation on hydrological cycle.
Please can someone give me tips even if you weren't or aren't with this exam board, im just really stuck right now.

Hi, the background review or literature review is the research you conduct on your topic before your investigation. I would suggest for the effect of vegetation on the hydrological cycle, you would need to talk about a.the normal hydrological cycle both global and local and b. different vegetation in your area c.the normal effects of vegetation and how this compares to other landscapes

What do you mean by background theory? Like the lit review?