The Fjord and it's glacier - Jakobshavn Isbræ is the place you need to see and enjoy. It's visible by foot and you just need to follow a trail that's starts behind the camping. The trail in it's divides in three ending path If I recall correctly. But the short version takes between 1/2 hour to 1 hour and you can miss the trail. The view is magnificent and there are at least two public benches on which you can stop, relax and enjoy the view. On your way back you'll go through the field where the local park their dogs, and dry some of the fishes that they fished.
The fjord is also accessible by sea - you'll just need to book a tour. I did a day tour and it's well worth the price. The boat tour take one to two hours and it's just so beautiful that you won't regret for a minute being either cold or on the boat. If I was ever to go back I would take a night boat to enjoy the ice with the very beautiful orange light from the night.