Here is an example tutorial on how to install and use podman from restartOS. In this example, we are going to use a backing disk at /dev/sda1 and we will mount it to /mnt/usb. We will use podman in the normal manner. At boot up, the install-podman script will be run against the mounted disk and will automatically populate the requisite folders to run everything. Here are the precise steps that will make this work. Note that the disk can be mounted through USB or whatever you wish.
sudo su
package install podman
echo "mkdir -p /mnt/usb && mount /dev/sda1 /mnt/usb && /scripts/install-podman /mnt/usb" > /scripts/startup/podman
make-persistent add /etc/ssh /scripts/startup/podman /etc/containers/registries.conf
reboot