I break this object into 3 parts to make it easier.
I draw the rectangle-semicircle combo on the origin. Rectangle has dimensions of 40mm by 20mm and semicircle has diameter equal to length of rectangle. I added the 10mm radius circle at the center of the circle and proceed to extrude.
I create new sketch at the front face of the rectangle. Draw the rectangle with the preferred dimensions and then extrude by 10mm away from the main shape
New sketch on the top face of new rectangle and draw rectangle with its dimensions. Extrude and add fillets.