check the battery to see if it is charged, and that the cables on battery are not corroided.
today for me...
truck, had to remove cable to deal with a steering column fix and removal of air bag. got things back together and click sound. did not have cable tight.
tractor, battery out of juice, put a charger on it. and got a spark were i should not have. off to find loose wire that is grounding out.
cheap charger for say $20 bucks. if it has a digital display, most likely you can use to check battery.
if you have a multi meter. 12.4v to 12.10v or is it 12.10v to 12.14v you should read. if lower you have a bad/dead battery possibly.
check battery water levels if it is a battery that has water in it.
safety switches, (seat switch for example)
not sure about tractor specifically, is everything in neutral / out of gear. no levers for FEL, rear hydraulics in neutral position, is PTO dis-engaged.