If you read up a bit here:
http://www.nivellsystem.se/images/stories/pdf_se/bygg.pdf
...and then call Nivell and explain that you need help with the floor construction, I'm sure they will help you with a good construction that answers your questions from the base plate up to and including the floor chipboard. For the overlying parts, the usual industry rules apply, which are discussed in all the threads here on the forum....
http://www.nivellsystem.se/images/stories/pdf_se/bygg.pdf
...and then call Nivell and explain that you need help with the floor construction, I'm sure they will help you with a good construction that answers your questions from the base plate up to and including the floor chipboard. For the overlying parts, the usual industry rules apply, which are discussed in all the threads here on the forum....