Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4797709.

This is a simple FreeCAD drawing and .stl model of a drilling template to fit a stock Creality brand hotbed, with the holes placed 170mm center to center.

The template itself is sized so the corners will touch but not cover the existing mounting holes in the Anycubic Mega Zero Y carriage plate, and was designed to assist in proper alignment for drilling new mounting holes to accommodate an upgrade to a stock heated bed intended for an Ender-3 or compatible.

Holes are sized to drill as 1/8" (3.175mm) which will give plenty of clearance for the stock Anycubic M3 bed mount screws. There shouldn't be any major problems if you need to drill out to 4mm or a bit more.