Need a instructions on how to remove the cowling from the subject lawn mower enjine.

Most B&S cowlings are held by 4 bolts around the bottom edge of the cowl mostly to the side and back. Since you likely want to do more than remove the cowl you may want to spend a few $$$ and get a manual. Operator Manuals, Illustrated Parts Lists & Wiring Diagrams - Briggs & Stratton

You will need to remove those four bolts that "ballengerb1" mentioned plus the two small screws holding the starter cover on and the one screw that holds the dipstick in place. It should pull straight up then. The tins around the sides have dimples on them that kind of snap into the cowling so there will be a little resistance when you pull it upward.