Assuming this engine is in the car I would take the #1 spark plug out and have someone bump engine over very slowly ( this can be tricky) a remote bump starter button works allot better.
Stick your finger in the spark plug hole when you start to feel compression your on the #1 cylinder's compression stroke, when the piston is all the way up ( some people use a long skinny screwdriver to determine this) the piston will be at TDC for #1 cylinder. Then you can drop your dist in making sure the rotor button lines up with the # 1 plug wire on the cap when the dist is all the way down.
If the engine is out of the car on a stand, I'd just do same procedure except using a crankshaft turning tool or a socket on the damper bolt.
When you do determine TDC make a mark on your balancer if there isnt one already and line up the pointer on the timing cover. It will come in handy later when you put a timing light on the engine.
Hope this helps, Charles