Welcome. Clean the key switch, check relays and do you hear the regular solenoid clicking sounds or not? How many hours, how old is the battery? BTW, Battery needs to read above 12.5 volts to be any good …
Try and jump start it, probably the battery, enough juice for dash lights etc. Probably wont do the starter clicking like on a car with a dead battery. My RTV had the same problem
Check your neutral lockout switch - if it thinks it is in gear it will not let the starter engage. Should be a relay in that circuit too that could cause the same problem.