Two things, first, #1 is at top dead center, second #1 is on the compression stroke. Pull the spark plug and hold your thumb over the hole while a helper cranks the engine over. It might take a turn or two till you get a feel for what is suppose to be happening. When you feel compression, you know both valves are shut and you are on the compression cycle. Slowly turn the engine till you see the timing ball or marker. Turn a little more and you should see a second mark not far from the first one, a diamond stamped in the flywheel?? This is where you set the timing. Double check by looking in the cyclinder to see the piston at top dead center.
Now, drop the distributor in place with the rotor pointing at #1 hole. It really doesn't matter where its pointing as long as you install the plug wires in order, its just pointing at #1 is the norm and caps are marked this way. Hook up the coil, cap and wires just as if you are ready to run it. With the hold down still loose, pull the plug wire from #1 cylinder and install a spare plug in the wire and ground the plug case.
Turn on the ignition to run. Twist the distributor body back and forth till you see the plug firing. Keep going till you get as close as you can with the distributor. It should take just a slight nudge to get it to fire. Once you are happy with it, tighten down the hold down bolt, plug in the #1 wire and you should be able to fire it off. Timing should be with in a degree or so of right on the money.
Joe