Please consider that accommodation is not included in the price of the training.
You might want to consider a bus pass available at Central Station in Karlskrona. Or there is a phone app for Blekingetrafiken where you can look up schedules and buy tickets with a credit card (in Swedish).
Here are some options for accommodation in Karlskrona that you can look at :
Special Offer: - 845 SEK for single room - 995 SEK for double room Breakfast is included. Monday to Thursday there´s also a complimentary dinner provided. See website for details. Ammenities: sauna, small pool and fitness room.