"TDC" occurs twice in the cycle. One is on "compression", the other, "overlap". If you didn't "blow" #1 (hold a finger on the spark plug hole while cranking until it "blows" your finger off the hole), you're not certain which TDC you're "at". You must be on "compression" for timing purposes.
You must also verify you HAVE fuel in the carb. Usually, operating the throttle will tell you, by watching for the accellerator pump "squirt".
Once #1 is established and you KNOW you have fuel and spark, use a socket to turn the crank (15/16" deep works well) set the timing mark on "12" (on the cover). Turn the key "on" and rotate the distributor back and forth, with #1 wire removed and held NEAR "ground". It will arc a spark when it hits the trigger. THAT is where you want to "start your search for the "happy spot". Often, "rocking" the distributor back and forth will get it VERY close.
"By the book", #1 terminal is at ABOUT 7 o'clock when sitting in the driver's seat. I don't think it really matters, but for consistency, we try to follow that.
NOTE: The term "cranking" means the engine turns over, not necessarily "firing". If an engine "cranks", it means the starter circuit is working. For clarity.