Most goods in Project EM, whether it's food and clothing, construction equipment, ship modules, launch systems, or even entertainment, have to be produced in an ERMA chain. ERMA refers to Extraction, Refining, Manufacturing, and Assembly. Each step in the ERMA chain is generally performed by a separate organization dedicated to that task. Not all products must follow the ERMA chain exactly; it is only meant to be a general model for understanding EM's production chain system.
Simple goods like food, for example, may only require an Extraction step (being grown by a farming company) and a Refining step (being sent to a processing plant) before being delivered to its end consumer. A far more complex product like an interplanetary freighter would have to have all of its numerous raw materials extracted and refined, sent to multiple manufacturing plants for construction of its separate modules, and finally have those separate modules assembled at an assembly plant (likely in orbit, in this example).
Extraction is the base level of any production chain. It usually comes in the form of extracting raw materials (for example: steel, copper, aluminum, gases, and oil), though it also encompasses the base levels of other production chains, such as the harvesting of food.
Refining is the processing step of the chain; it encompasses any process necessary to turn raw materials into usable refined materials. It is the final step for the most basic products, like food.
Manufacturing is the step of the chain that takes in refined materials and turns them into useful products. This is typically the last step for less complex products that require no dedicated assembly plant, such as firearms, clothes and mining equipment. Other products, such as tank turrets, rocket engines and tires will go on to a final assembly step.
Assembly is the last step of the production chain for the most complex products like personal vehicles, interplanetary vessels and heavy construction equipment. An assembly plant takes in manufactured products and outputs an assembled final product. It can often take place in orbit for large spacefaring vessels that aren't intended to go to the surface.
If a certain good is produced in excess of its collective demand, it may be sent to a Storage Facility. Storage Facilities serve as an existing source for that product before it's determined that more of the product needs to be made. It is possible for individual storage facilities to be destroyed or captured by hostile forces. In addition to product storage, the overarching storage system is also used to maintain supply reserves for individual consumers units, as their reserves are essentially treated like storage facilities according to their capacity. Storage facilities and supply reserves are able to have a Minimum Count, which automatically requests more of a certain product if its count falls below the minimum.