Expanding a group in a Lovelace view?

I created a tab “Devices” in my Homeassistant webUI by adding the following text to ui-lovelace.yaml

  - title: Devices
      - title: Status
        type: entities
          - group.all_devices

I logged out and back in to the WebUI (I guess that is required, right?) and I see the new tab which contains the defined card.
But the card just has one line: all_devices
How can I get Lovelace to expand that group and show a list all my devices in that card without having to type them out one by one?

I spent a few hours going back and forth in the docs, but I didn’t get any wiser. Any pointers to good documentation on Lovelace configuration in yaml mode would also be appreciated as well

Thanks so much to all contributors for your awesome work.
Home assistant rocks !

This will do what you want:

Lovelace custom card guide:

Lovelace built in cards (left hand menu);

Hi @thomasloven
thank you for your answer.
I am still learning Home Assistant.
Custom plugins go a bit above my capabilities (for now)
I assume this means that what I was asking for, is not possible with the standard Hassio.
I will revisit your solution in a few months, when I am hopefully a bit smarter on Home Assistant
thanks again,

This is not required. If you’re using YAML mode, just click the three dots in the upper right of Lovelace and select Refresh.

For the next person that finds this thread:

type: 'custom:auto-entities'
  type: entities
  title: Bas' iPhone
  show_header_toggle: false
    - group: group.iphone_bas