Docker Erpnext Custom Hrms

Hi I follow this tutorial but still not clear on it: frappe_docker/docs/custom-apps.md at main · frappe/frappe_docker · GitHub

apps.json
export APPS_JSON=‘[
{
“url”: “GitHub - frappe/hrms: Open Source HR and Payroll Software”,
“branch”: “version-15”
}
]’

export APPS_JSON_BASE64=$(echo ${APPS_JSON} | base64 -w 0)

For the dockerfile I use this one: frappe_docker/images/bench/Dockerfile at main · frappe/frappe_docker · GitHub

For the pwd.yml:

After I build using this command: docker build --build-arg=APPS_JSON_BASE64=$APPS_JSON_BASE64 .

What should I do next to update the base image to my pwd.yml, any help would be great?

One of the errors is the --file=images/custom/Container which says the file is not found.