Bon voyage...I'm in Sweden!!

I'll assume you flew to Gothenburg Landvetter (GOT) Airport. Hopefully, you won't have lost a flight, been delayed 4 hours, have the airline lose your bag and then end up staying the night there.

So you'll need to know how to get to Jönköping from the airport. You could maybe buy a bus ticket in advance, but I would just wait, because you'll probably run into some delays.
When you walk out of baggage claim you'll find a small market called Pressbyrån where you can ask for the next bus to Jönköping (tell them you're a student and ask if they can give you a discounted price-not sure). It should cost you something like 79-89 SEK. This bus will take you directly to the Jönköping train and bus station.