My own slightly modified version of the instructions on setting up a containerized Huginn instance with Lets encrypt that can be found here https://docs.bytemark.co.uk/article/how-to-deploy-huginn-on-your-own-server-using-docker/
Check out the project and run the setup.sh script.
There is no admin user created, but instead a invitation code has been created in the .env file that can be used for new signups.
Inside the .env file, all domains that will point to the server can be set with the HUGIN_DOMAINS value, seperated with a ",".
Traefik will automatically configure a Lets Encrypt certificate for all the set domains. Comment out HSTS line in docker-compose when forcing TLS.
A password will be generated for the Traefik and phpmyadmin dashboards and piped out to a file called auth-password.txt. Copy the contents and delete the file!