User manual online explains procedure. Remove passenger cowl, using key as on 1199. You need to remove both seat side panels then unscrew extensions. Replace side panels and fit passenger seat. Not exactly a five min job or as simple as on the 1199, but easy enough.
I have only looked inside of rear seat. Centerpiece is removed with a key as previous cowl. Side flaps or wings are attached with Torx-screws if I remember it correctly. So pretty easy.
At the same time this is the reason why I love this brand. To make it more beautiful, they'll sacrifice without a blink some usability. Would you see Honda making this? And is this motorcycle really for hauling two persons? It is not.