Enclosed with your new Lewis Winch, you will find the Universal Adapter Kit. Choose an adapter that fits the sprocket on your chainsaw. You will also find a thicker adapter with counter-sunk holes in it. This is the one that fits the Lewis Winch. Now bolt the 2 adapters together with the 3 bolts provided.
Use some "Loctite" on the treads so the bolts star tight. Adjust your chainsaw "tension er" so the lip fits in the smaller slot of the casting. Line up the adapters and the studs on your chainsaw with the slot of your portable winch and install the 2 nuts. The unused adapters are for other brands of saws.