Just loosen the three bolts while the belt is still on, that will help hold every thing still, you still might have to hold it by the crank bolt though.
Factory setting for those cam bolts is centered in the slots.

On re-assembly, belt must be tight between the two cams and then down from the intake cam to the crank. Must remain tight in thos areas, some have use zip ties to hold the belt in place while the getting the tensioner in place.

DanR '94 964 342,000 miles (108,000 on the new engine)
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DanR