The board says “Melzi Ardentissimo” and does have a sd card slot, so I guess first step would be to find an old, blocky mini-usb cable, haven’t needed one of those in a hot minute, and backup the firmware.
And it looks like it can just print from the SD, but since there is no display or controls of any kind and the sdcard has multiple printfiles, its probably sime kind of magical filename…