On your map will be briefcase icons, each one represents a business that can be bought by the resistance to produce things or just earn money. Use the "Map Info" feature to click on them and find out what they are. Businesses are mostly unique to each map and depending on their type may require input items.
To buy a business just travel to the location and use the Y menu.
Businesses are managed in the "Resistance" screen and require staff to operate. More staff will produce the items faster. Staff are paid wages hourly from your resistance funds.