If you do not know where to go, then visit rejseplanen.dk (click on the logo). Here you can enter where you are and where you're going. Then it shows you which bus to take, and where to go.
NT (Nordjyllands Trafikselskab) is responsible for bus transportation in the North Denmark Region including city busses in Aalborg.
In the buses you can buy a ticket for approx 20 kroner.
It is much cheaper to travel with a travelcard - called "rejsekort". Visit Rejsekort.dk for more information
You can also buy a 'periodekort', which allow you to travel as you like for a period of time. To acquire such a 'periodekort', go to the NT point of sale, located in the Kennedy Arcade at the bus terminal near the center. This is cheaper if you travel frequently by bus.
Read more about NT by clicking on the logo.