I still have one sitting in my garage, still fun to ride every once in a while.

First try new gas mixed with new oil. Make sure there are no big intake leaks behind the carb. If you can't crank it by hand try push starting it, sometimes if you keep the engine cranking it will catch. If nothing else works try a little starter fluid, not much because it's a small engine. If that doesn't work you probably have to completely disassemble the carb and clean it all out with carb cleaner, squirting cleaner through all the passages and jets from every angle until they're flushed clean. I had to do that after leaving mine sitting for 2 years with a blown engine. Make sure it has compression, make sure the magneto is working and you're getting spark, make sure the carb is properly delivering fuel, and there's really nothing that can keep it from running after that.