Download the Raspberry Pi image from https://en.opensuse.org/Portal:MicroOS/Downloads and copy it the MicsoSD card.
# xz -d openSUSE-MicroOS.aarch64-ContainerHost-RaspberryPi.raw.xz
# dd bs=4M if=openSUSE-MicroOS.aarch64-ContainerHost-RaspberryPi.raw of=/dev/mmcblk0 iflag=fullblock oflag=direct status=progress; sync