how to add my scheduler to linux kernel

Question

I'm working on a research on linux kernel. I should add a scheduler algorithm to linux kernel, like SJF, SRT and any other algorithms. After some searches I found that linux kernel has tow schedulers: CFS and real-time scheduler. but what is difference between this tow scheduler? How should write my scheduler code? where I should add my scheduler code, CFS or real-time? should I do this work before compiling linux kernel? and any other things that I need to do this work... I'm using linux kernel 3.15.6.