I recommend printing in the given orientation (standing up) with mouse ears on the corners.

It can be attached to an octagon plate with two to four Panel-to-Tile T-Bolts or Snap-to-Snaps, or it can be mounted to a wall with screws through the small thread holes. There must be at least 3 MU of clear space above the mount to fit a battery. Two panel-to-tile t-bolts or two snap-to-snaps should be fine for most batteries. If you're really rough with some 15Ah Flexvolt batteries, you might find that the strongest way to attach the mount to a plate is with two directional snap-to-snaps in the top corners, and two standard snap-to-snaps in the bottom corners.