CML & SML & CAPM

Hello everyone! I’m so glad to be a member in this forum. I’m having difficulties in studying SML, CML and CAPM. I understand their definition, like the formula of CAPM, the differences between SML and CML, but I don’t really know how to put them together and make use of them. Could anyone help? To be specific, SML and CML are both derived from CAPM, however, what are their roles when it comes to portfolio management?

https://www.analystforum.com/forums/cfa-forums/cfa-level-i-forum/91310543