Explain how cholesterol metabolism is regulated by internalized cholesterol?

I have been reading up about this quite a bit but find a lot of contradictions and irrelevant information. From what I have learned I know that HMGR plays an important role in regulating the synthesis of cholesterol but I am struggling to understand exactly how it does so. Also, are there any other ways that cholesterol synthesis and metabolism is regulated by internalized cholesterol?

Have you looked into SREBP?

HMG-CoA reductase catalyzes the first committed step of the biosynthesis of cholesterol and other compounds.  Therefore, it is heavily regulated, and the regulation occurs by multiple mechanisms.  When one considers what conditions are expected to bring about the fastest rate of cholesterol synthesis, it might be helpful to look both at the concentration of the final product cholesterol and the energy status of the cell.