Sup..
Basically WAM means Weighted Average Mark. As the name suggests, it's the average of all your marks over 100. So yeah, it also includes the fails. You should also notice that each subject has their own credit point values. WAM is pretty easy to calculate actually, it's the sum of your marks multiplied by your credit point value, all divided by the sum of credit points done.
GPA is a stupid system honestly. Each university kind of has their own GPA system (i.e. the points associated with your grade). Basically, just sum up all Grade Points multiplied by credit point value, divided by total credit points attempted.
Hope that helps.