How to access the folders? (etc/opt/...)

[mario-g0]

In all the docs I can't find any instruction on how to access the various folders talked about.
I'm on macOS and I see a connected device called "kios-some numbers", if I click on it it shows 2 folders web and machinery, but trying to open it and it closes the connection (the original element can't be found)
where the hell is etc/opt/blablabla? how am I supposed to retrieve the video files since the web interface doesn't even display them?