So, this is designed for a 6V AA battery pack (btw I got the pack accidentally rotated 90 degrees, spin the mounting holes!) and a 5x7cm protoboard (the double sided ones) and of course those yellow gearmotors.
The center of gravity is a bit low, so there is a bolt pattern for an 'upper stand' (I have not designed it yet)
Screw holes should auto-thread M3 screws, depending on your printer they might come out a bit small.
I'm still trying to get my robot to balance, good luck!