explain the triangle, circle, and square marks on a 1995 5.7 chevrolet crank shaft timimg gear, witch one do you use to aline the camshaft?

I found out, the triangle mark is top dead center on the crank shaft gear, so you line up the camshaft gear mark at 6=O'clock to the crank shaft gear triangle mark at 12- O'clock. Different manufactures will mark certain degrees on the crank shaft gear, but you need to know witch one is top dead center. Some or most only have a dot at TDC on the crank shaft gear.