For an engine to run it needs gas, compression, spark .
If you pull the cord does it ave compression?
Do you have the oil/gas mixed right ?
Take off the air filter and cover the back of the carb with your hand, if it tries to start remove your hand.
Check the kill switch for a grounding out , remove it temp.
Check the coil gap , you can use a business card for the gap .014 or so. remove the starter cover loosen the two coil bolts
pull up on the coil and turn the flywheel around to the mag and insert the card , lower the coil to the mag and tighten the bolts.
if not the carb could be bad.