How do I not kill this thing😭

Hello! I am an experienced (5ish years) plant collector but only recently have gotten obsessed with begonias. Bought my first two at a local plant show this weekend!! Ik buying a ferox as one of my first two begonias is naive but I am a young and have childlike hope. How do I help it adjust and keep it happy? I have it potted in half coco coir half orchid mix (bark, perlite, charcoal). And I don’t have a cabinet or terrarium, but i live in the south so my place is baseline 40% humidity, 60-70% with the humidifier. I feel it already has a little bit of yellow spotting. I want a luscious one of these so bad! Pic + bonus pic of my little kingiana included