About selling reports

hi everyone
I’m new user of erpnext open source and I confused in different aspects. One of them in selling module ( main and standard reports). what the purpose of them? and what is the Sales Analytics, Sales Funnel, Customer Acquisition and Loyalty etc …
Actually I must understand this tools in shortest time cause I take it as a project in my course so maybe I will return with new questions.
thank you.

@A.S, have do you take a look into demo.erpnext.com? With data, will be more easy to you understand these reports!