There is no cadet program with Norwegian now, or within the near future. Again why it is on their website at the moment, is beyond me, but I have from a top source that at the moment this is not an option. No pilots below 1500 hours, will be employed at the moment, and it is preferred that most of this time is on type 737.
I guess they might be testing the waters for this, since they are setting this on their site, and things might change, but from my source it is very unlikely any changes will be any time soon, definitely not this year!