The society model covers the whole life cycle of a colonist. Young colonists can go to school (if you have one available) and then to college. As the colonists get older they then start working and establishing businesses and earning what they need for living. If there are no jobs available and they have no cash, they will move away unless you provide them with unemployment benefit.
The practical skills and knowledge of workers and managers affects to how efficiently the work is done. If you have skilled workforce in a factory, for example, it will produce more than a factory with less skilled workforce. If you like, you can allow your colonists to became private business owners. In this case they will send you building requests and you then decide, which private businesses are allowed.
To be able to operate defense systems and to build buildings owned by the public sector you need to collect taxes. The tax model can be flexibly chosen from anything between flat tax to a progressive tax model, in which rich colonists pay more taxes than the poor ones.