Trying to install Akaunting as custom docker app

I am new to Truenas and using dockers. I have my setup working as expected and now branching out to custom apps. I would like to install Akaunting which has a docker app but I cant find step by step instructions on how you get it installed with Truenas.

Is there something unique about Akaunting in this regard? Because otherwise, the Custom App docs would seem to cover what you need:

I tried following that but got an error: Failed to apply default image tag “github/akaunting/docker:latest”: couldn’t parse image reference “github/akaunting/docker:latest”: invalid reference format

Also: Error: InvalidImageName

I’ve tried both the git repository link (GitHub - akaunting/docker: Docker Image for Akaunting) and the pull code from Docker (docker pull akaunting/akaunting:latest ) neither works

*Since I’m new I had to remove the links but hopefully it still makes sense