New to Sweden Taxation: Are there additional costs to the 30% tax on stock profits?

Its tax season and this will be my first time doing a Swedish declaration. Currently from my understanding, profits are taxed 30%. But I'm a little worried because I have been Swing Trading this year (lots of buys and sells) and I noticed on Skatterverket's website, it mentions something about "overhead" costs (omkostnadsbelopp) but I don't know if this is poorly translated.

Aside from the brokerage fee, is it only the 30% from the profit that is taken? Or are there other hidden costs?