and your question is? You mean what the "modes dial" does? It lets you choose if you are photographing faces, flowers, nature in large, panorama, and there are several manual modes like AV, M, Bulb, etc. Info can be found in your manual what each of these do.
If you found the body and the 24-105 L lens separately for less than the kit, I would say that is an exception and maybe you've found a rare deal. At the time of this writing, here on the amazon the body is $1800 and the lens by itself is $1100, for a total of $2900. The kit is usually $2500, but appears to be on sale for $2400 at the moment, which is hundreds less than you would pay separately.