50/50 Melfest-style votes for the first part, which benefits televote-friendly songs (like, hopefully, KEiiNO and Hank). The top four then advance to a superfinal (or "Gold Final"), at which point things get a bit more confusing. To quote from Wikipedia:
"In the gold final, the Norwegian viewers vote alone. After a short replay of the songs, the four gold finalists are put up in two pairs. The winners from each pair will then meet in a gold duel. The gold duelants takes with them the votes from the gold final's first part. The votes of the gold final and the names of the international judges will be published on NRK's website after the final."