Dear tutor, I read about SML and CPL and understand that SML relates to the expected return of efficient and inefficient portfolio and CPL relates to...

Dear tutor, I read about SML and CPL and understand that SML relates to the expected return of efficient and inefficient portfolio and CPL relates to efficient portfolio only. That's all I know. However, I don't think I grasp the concept deep enough and don't quite really understand the differences and functions, applications etc. Have you got a great explanation to help me to enhance my understanding of the differences in more detail? Thanks.