what you will need

1) a squared piece of wood, scraps will do so long as the piece is true and square.

2) a saw.

3) marking knife.

4) a drill

5) and some clamps.

Step 1: Sawing

once you have a square piece of wood

from one corner to the other mark up.

then saw from the corner to the opposite, leaving 2 pieces like in the pic

Step 2: Use the Clamps Jaw As a Template

now place the clamp on the wood and draw around the clamp

do this twice

with your drill ( i used forstner bits for drilling.)

drill out the 2 markings you made earlier

until both bits of wood have 2 holes

now you can clamp those tricky corners for example while making a frame or drawers

and that is that

thanks for looking

and be safe

take care all.