SAP MM Functional Specicifcation

Hi Guys

I just got trained on SAP MM, and the writing sap mm functional specification has been a big problem to me. I have came across many question on this and have seen similar answers to it but still don't get it.

Please, as a new person and someone who don't know what is this all about and have not seen example. Can someone please tell me what this is all about a written example and please a link and where I can learn about this comprehensively. I have seen a mere sample and template how it looks like, please now in a reall life I want to know how this looks like with example specifically in sap mm