DSB is responsible for the majority of train transportation in Denmark.
If you are planning to travel longer distances, taking the train is usually the better option. The train leaves from Aalborg at Aalborg Station, Aalborg Vestby and Lindholm in Nørresundby.
You can buy a ticket on DSB's website (click the logo). You can also buy your ticket at the trainstation, either at a ticket maching or by asking an employee.
You can also use the danish travel card 'Rejsekort' to travel with both busses and trains. Learn more at www.rejsekort.dk.