You will need three types of buildings to produce useful goods, complete orders and earn coins.
Trade Center produces raw materials that you will need for further production. By leveling up, you will be able to open more cells.
Mines also produce raw materials, which will come in handy for completing orders. You can produce equipment for Mines at Equipment Factories.
In Factories, you can produce unique goods from raw materials obtained in Trade Center and in Mines. Each factory has its own range. For example, in the Household Goods Facility you can get fasteners, paper and ceramics, and in the Tool Factory - scissors and hammers. You can build one factory of each type. The higher your level is, the more Factories are available to you.
In the Warehouse you can store raw materials and products which are manufactured at Factories. Upgrade the Warehouse building to get more storage space.