Can I program my own key FOB for a 2018 Outback 3.6R Limited?

I just bought this car. It came with a spare key that wasn't programmed.

Control+F shows 204 mentions of key fob in the owner's manual. I've found mention of how to deactivate fob functions but not how to program a "blank" fob.

Am I overlooking it? Can I do it myself?

TIA!!