It should be completely possible using only the official install media, then and now. To do this today, download the AMD64 install74.img (like an ISO, but for flash media), write the image to a USB disk, connect to the APU1/2 via serial, plug in the drive and power up the APU, then follow the installation script.
Once booted, run fw_update and syspatch to make sure the firmware and system is up-to-date.
