Hi Dominique,
The link @lagapidis added is the most complete list of BGP attributes and the path selection:
I didn’t include multipath because by default, it’s not enabled in BGP. Internal and external BGP only install a single best path (unless you enable multipath). If you do use multipath, it’s good to know how BGP deals with it.
The minimum cluster list length is a similar example. It only applies when you use BGP route reflectors. There are also some exceptions when you use BGP confederations.
I’ll add a note in the lesson that explains these possible extra steps. I don’t want to confuse people new to BGP too much with the terminology that is a bit more advanced level 
Rene