Use the search engine for "wont start", there's lots of info.

You need to deliver high current to the starter to get it cranking
that means a good battery and solid battery cables and connections.

The solenoid needs a good connection through the interlock switch and the ignition switch.

You might try jumping the starter direct and see if it behaves.
Then you can narrow down the problem area.

If the starter gags with a direct connection to the battery then
you can suspect the starter motor.

Bill