...
Take the drilling template and place it onto the BATMThree, so that the lock will fit into cutout in the template.
...
Mark Dint (dintmark) the holes with a center punch.
...
Drill holes into the marked positions. This step is critical, please follow these recommendations.
...
Drill a small (3mm bit) dint (do not yet perforate) and compare its location to the drilling template.
If you can see bare metal while looking perpendicularly through the drilling template, you are in the correct spot.
Use that dint to guide the final drill locations (7mm bit recommended).
...