Select a plane
Select sketch tool
Select line tool
Draw lines
Select filet tool Select the corners
Change size to 5mm
Exit sketch fillet
Exit sketch
Select
Change to 100mm
Change to 3mm
If OK click tick to accept
Select this face
Select sketch tool
Select circle tool
To draw circles click to identify middle, click again for the outside
Exit sketch
Extruded cut
Change to 3mm
You may need to select the circle
If OK click to accept
WELL DONE