Sorry, I'm not going to be able to help you. I don't have any experience with S3Bubble. I'd also caution you against getting locked into any form of subscription service for your channel. Especially one that does not provide enough help to guide you through creating your channel. There are other available options to developing a channel. If you're interested, have a look at the software I provide in my signature at the bottom.
Again, sorry I could not be of help...
FREE Windows desktop software for converting Direct Publisher channels to SceneGraph (SDK), for creating
BIF (Trick Play) files,
Roku (MRSS, JSON) feed files, and
FireTV feed files @
GitHub/rrirower.