Assuming you have the correct distributor parts and installed correctly:
First turn it over to where you think it is on TDC for #1 (the front most cylinder)
Pull the front valve cover off and visually verify both valves are closed. Then turn it a bit more and verify the exhaust valve starts to open. If correct, back it up to TDC, if not go one rotation, verify and then set up to TDC.
Very important, verify all your plug wires are fully seated in the distributor, coil and plugs.
If everything is at "factory spec" your distributor should be pointing to around 7:00. (If not report back)
Verify the plunger in the distributor cap is fully extended and not stuck in the cap. Then reinstall and use the locking clips on the distributor.
Loosen the distributor lockdown nut so you can rotate the full 10-15 degrees in both directions. Set mid position to start.
Next you need a tester to verify the plug is firing. I use a cheap Neon AC tester (buck or two at Home Depot). Pull the plug wire off, insert one lead of the tester in the plug wire connector, the other lead to a solid ground (Just use an alligator clip jumper wire to ground).
Now the test:
Turn on the ignition, don't touch the starter. Did your ammeter slightly deflect to the left?
Now turn the distributor body back and forth the full rotation allowed by the distributor lock bolt you should see a flash on the tester when the points open. If it flashes your ignition is fine.
If it doesn't, start working backwards. Next try the tester at the cap where the plug wire goes in. Still no go? Try the coil wire at the cap, then at the coil.
Then report back what you found and we can figure out the next correct step.