with piston at top dead center , Look at the cam and find the middle point of the overlap. That is where the two lobes meet. There will be a spot where they will lift the valves, or lifters approximately the same amount. the exhaust is closing and the intake is opening. Put that pointing to the center of the lifter boss. that will get you close enough to fine tune it with the degree wheel. Usually won't be off more than one cog.Use the centerline timing to get it exact.
Or look up the specs and see the timing of the center-line of Of either lobe and set the degree wheel to that degree , install cam with that lobe pointing exactly towards the lifter hole.