Same here — once you get the scrolling part it's pretty great, but like you I was stuck at the top for a while. A downwards-pointing arrow on the hero would help a lot here.
Firefox in Windows has the tiniest little scrollbar indicator in the top right that honestly blends in very well with the background. I didn't realize I needed to scroll until I came to the comments. I clicked around... got some interaction... but basically left the first time being very confused.
I have Firefox on macOS as well, but I don't see a scroll bar until I start scrolling. Could be because I'm using an external trackpad, and not a mouse.
