From Kastrup airport (Copenhagen) to Helsingborg there are two main roads:
Train at the Swedish side over the Öresunds bridge or on the Danish side with a boattrip from Helsingör to Helsingborg. Either way you decide to take the train leaves from Kastrup airport and the travel time is about 1,5 - 2 hours.
The train departures on the Danish side every 20 min day time and every hour night time from Kastrup to Helsingor. See time schedules:
Train and
Boats
When you arrive at Helsingborg you are going to stay at either
Hotel Mollberg or
Hotel Marina Plaza. Information about which hotel you will stay at will follow. Hotel Marina Plaza is next to the ferry and train station and Hotel Mollberg is a 5 minutes walk from the ferry and train station.