"How do I build a fighter?":
Fighters are built using a special form of industry - Fighter Factories. To build fighters, you need to have design a fighter class and to have already built some fighter factories. Go to the Industry tab of the Population and Production (F2) screen. In the "Construction Options" pulldown, select "Fighters" You should see a list of the fighter classes you have designed. Select one, and enter the number of fighters to be built, the percentage of fighter industrial capacity to apply to the task, and the TG into which the new fighters should appear at the bottom of the panel, then hit the "Create" button to create the task.