Hi Jack,
I understand you are using Enterprises for Office 365, and you would like to know the way to access your public-facing website modified page.
For Enterprises users, I would like to specify that the public-facing website is a as a standalone site collection, this is different from Small Businesses users. The suggestion in this thread about logging into website, I always referred to public-facing website. The “Website->Web Pages->Pages” I referred to:
In addition, in order to avoid confusion, we recommend creating a new dedicated thread with detailed description about your requirement, so that we can dig deeper into this question. Thanks for your understanding.
Regards,
Maggie Li