Sort:  

I think is not possible yet, I'm gonna ask around to see if someone else knows. I'll let you know.

well, you can upload them vertical and then you use the full screen option and you will watch them vertically in phones. Otherwise, you'll see them like you said.

I try but still look like this when its on full screen

yeah, it only works on phones at the moment, on PC they still look like that. I went to watch one video on phone and PC and ir only worked on the phone