Fill the Service Group Name (1) and then fill the DOMAIN (2) variable with the external domain you wish your Squidex instance to be available on.
You can leave the Branch field at the default master.
When you are done, click Apply (3).
When it's finished, click managed resources (1).
Click squidex_squidex (1).
Your URL (1) will be just below the service name.
You should then be ready to go!
Please check the logs by clicking Logs (1) in the service page.
It is very likely a configuration problem and not related to hosting under Docker. Checkout