developer documentation for Episerver 6

I have just been tasked with making some changes to an Episerver 6 site which is still in operation. I learned on Episerver 7.5 and have only had 7.5 and above experience, and I cannot find any information on how to develop for 6 - can anyone help me? I just need to create a new page, but do i do it first in the CMS, or in Visual Studio, and how does one know about the other?

Thanks,

Marshall