Always remember the four requirements for a gasoline engine to run:
Fuel
Spark
Timing
Compression
The first two are the easiest to check, and often are the cause (especially on a newer engine).
Pull the plug, ground it on the engine while pulling the starter, and watch for a bright spark. (Don't zap yourself). Replace plug if needed.
With the plug installed, pull the starter, remove the plug, and see if it is wet with fuel. Check the fuel lines? Maybe a carburator problem? Old fuel? Carburator would take too much explaining for now.
Timeing? Did you hit a big rock and maybe shear the crankshaft key?
Compression? Need a tester. Maybe a valve or ring problem. Requires some skill to repair.
Try the easy things first. Plug, fresh gas, etc..
Good luck