PPM - calculation of metrics

I'm completely at loss. I'm reading all the help + img-documenantion, but i'm not able to figure out how to get a calculated metric. E.g. a simple figure where I have $/per weight * weight = X $.

I understand the metric definition part, but cannot figure out how to customizise and configure the program to calculate it.

ANy pointers, documentation etc appreciated.

Regards,

Espen Leknes