Installation with dependencies

Hello,
I would like to install ReflowHQ ( https://reflowhq.com/ ) under October. The store setup (html toolkit v2) is easy to install, but what I need is authentication and paid subscription. After tens of hours, I still can’t get it to work.
I’ve tried the Vanilla.js installation
I installed the dependencies at the root of template…
in short, I must be missing the little thing that could make it all work…
If anyone could help me, it would be much appreciated.
https://reflowhq.com/
DOCS: Getting Started | Reflow