One question...

Theme: Front panel

How can I create a flat milling for a screw at the rear?
How can I place a 1mm deep flap countersink with d=5.2mm on the lower (rear) side of a front panel drill hole?

In addition to a drill hole, please make a round flat milling on the back side:

1 (Image 1: Round flat milling at the rear)

Please note that the corner radius must be exactly half the diameter!