Everyone here is saying the same thing actually, however you need to do this methodically and forgive me if it seems I am talking down to you, but this is the best way to explain it; a car needs 3 things to run; fire (spark), air, and fuel (actually 4, it needs compression as well for it to run as you would expect). So, here is what you do;
1. Air - no issues unless you have a rag stuffed down the carb or the throttle plates are not opening at all (i.e. choke not working)
2. Fuel - easy to check, take off the air cleaner and work the throttle and see if fuel is squirting in. If not or as a test, splash a little fuel into the carb (just a little like bottle top cap worth or 2). Try and start it, If it fires even a little (where it didn't before, fuel delivery is your problem)
3. Spark, easiest way to check, remove a spark plug wire off of one of the plug, take a old spark plug (doesn't have to be the right one for the car, just anyone will work), connect the wire you took off to the spark plug you are going to use for the test, ground out the bottom (the J shaped metal on the bottom) by holding it to a bolt on the engine or use a lead with clips; turn the car over and watch the spark plug to see if there is a spark jumping across; if not then you have a problem.
So, once you have narrowed down which area is the problem you can then chase it down. Here are some common issues
SPARK RELATED
1. bad coil
2. bad ballast resistor
3. broken or disconnected wires
FUEL RELATED
1. plugged fuel filter
2. bad carb (floats malfunctioning and not set correctly)
3. plugged fuel line
It isn't rocket science or difficult; it is frustrating for sure but if you take your time, check each thing thoroughly and one at a time you will find it. Since the car was running and now isn't, it is something simple. That doesn't mean it will be easy to find, just that when you do it will be a "ah hah" moment. Last thing, do not blindly trust parts store parts; "new" doesn't always mean it works. I have bough coils and ballast resistors brand new and had them be bad.
Good luck