Starting, ignition timing question

[66clow]

I recently replaced my intake gasket. Truck was fine drove home from the shop i worked at. Went out today and truck started fine but cut off since it wasn't warmed up. But went to start again and it wouldn't kick over. Sounding like it is not getting a spark. I'm getting gas.I found the bolt loosened on the distributor that locks it down. Thinking the timing moved, how do I line things back up to make sure timing is right. Thanks