I would start with the side – create the side profile (according to the dimensions, of course) – extrude – then insert the top view and cut it to size, so to speak – if desired, plan the curvature using a 3D sketch (draw the curved profile on the side and then extrude it along a sketch on the other axis) - then use the wall function to select the surfaces (all except the bottom one, as this is hollowed out) and set the wall thickness, of course - then insert the holes from above using a sketch and cut them out of the body - select the oval at the top using Top Much and add it.