Dell Inspiron 5520 :: How To Switch Manually From Intel To AMD Radeon Graphics Card

So I recently bought a laptop (Dell Inspiron 5520) with AMD Radeon 7670m HD graphics cards. However, the laptop came with another graphics cards too which is I suppose called an integrated graphics card. It's name is Intel HD 4000. So basically I was on a site which told me whether my computer could run a specific game or not. I passed everything like processor speed etc. but the graphics card. It said I use Intel 4000. I checked from some other applications and those also told me that I was using Intel 4000. I want to know whether I use both graphics cards or just Intel 4000 and if that is the case how I can switch manually from Intel to AMD Radeon graphics card.