“Materials meeting these conditions then need to be selected for use in production at the facility/station. There are two ways this can be done.

Inventory: The Raw Materials inventory has a 'Mark For Usage' option that allows the assignment of materials to facilities and stations owned by you or your faction and meeting the location requirements listed above.

Production Interface: The interface has a 'Materials' window that displays a list of all available and selected materials for the facility/station and allows selecting or unselecting them.

Those available materials that are selected are then used in the materials counter on the 'Add' window and when starting production. Materials in the facility/station doing the production are used before materials elsewhere.  ”