Hi,


Welcome to the forum.

To answer your question:

It's not a different method of creating the resource - just assigning the resource. It sounds like you have already created the material resources. Set their cost per unit (tonne it sounds like.) Then split your screen (Window - Split). Select the task in the top pane and in the lower pane, select the resource from the drop-down. In the units field enter the usage per day in the format: unit/day. So, for example if you use 300 tonnes per day - 300/d. If the duration of the task expands or collapses, the 300 units per day stays stable.

As a note, materials resources will not be automatically flagged for overallocation like work resources.

I hope this helps.
Julie