That bit of text is not really designed for the OSPi but rather the Arduino device (which no longer supports hosting the UI assets from the SD card).

You are welcome to follow the same guide: https://opensprinkler.freshdesk.com/support/solutions/articles/5000164006-using-a-different-server-for-ui-assets to setup the Apache hosting. Specifically, it will be option 2 of that document.