Reference a chainsaw sharpening angle chart, for help determining the proper angle. From that initial cutter, proceed to file every second cutter around the chain. Now reverse the saw and proceed ...

and you can find this number either printed on the blade itself or in the user's manual for your chainsaw. After you've attached the proper-sized grinding stone and the sharpening angle guide ...

Position the guide on the cutting bar so the cutters ... then readjust the grinding angle and sharpen the remaining alternate ...