I have Home Assistant (latest version) and already have spent more than an hour trying to figure out what I’m doing wrong: In all the tutorials and also on the HA demo site ( https://demo.home-assistant.io/#/lovelace/0 ), on the top right, there are three dots that allow to switch to the “Configure UI” mode to edit the frontend. However, in my HA installation, I don’t find these three dots and also nowhere else an option to switch to an editor for Lovelace.
I don’t know for sure, but I think you have to the logged in user ( in the left sidebar the lowest option, normally your name), and then turn on ‘advanced mode’
Perfect, this was it! I wouldn’t have guessed that one as I thought it’s not too long ago since I installed Home Assistant (but seems like it was after all). Your screenshot also answered the next question I would have had - how to switch to Lovelace.