Hi Daz, here is the tank pressure set-up as mentioned by Martin. You would need to buy a starter such as a Sullivan, and find a suitable small V belt (around 6mm wide ) from model shop or sewing machine specialists (or via boat racing club source). You will need one which is long enough to clear the deck of the boat by around 3" so the starter can be used horizontally (as in Martins drawing)
Years ago we used to use a square leather boot lace to start boat motors. You don't wind the cord round the flywheel,- just loop it under the flywheel and holding the boat down firmly (a helper is good for this) using both hands, apply tension to the cord and pull up (to make the flywheel move anti clockwise (from the front of the motor), - slacken the tension, bring cord back and repeat ( sort of zip the cord back and forth quickly, - tension pull,-relax pull back etc).
You will need to prime the motor by hand (finger over carb while turning anti clockwise by hand till you see fuel coming down the line and into the carb . If motor locks, it's flooded,- remove glow plug, spin motor with cord or starter to get rid of excess fuel, replace plug (do not overtighten plugs,- firm is fine) and re-try. Experience will get you sorted. As martin suggested, a good idea would be to go to your local boat racing club for direct advice.
Make sure you start on very low throttle to avoid over revving the motor and get it in the water as quickly as possible to avoid overheating. Hope this gives you a bit more of an idea.
See guy using cord starting in beginning of vid. Pic of green boat is one I built around 1977 and has the same O.S Max .40 as yours. Went quite well and very reliable.