You need to find out first whether the battery is good or not,and also if the system is charging.
If you don't have the means/tools nor knowledge to do it,have the battery checked out. If it's bad,replace it,see if the tractor will start,then before running it too long,check the charging system. If you have a voltmeter,with the engine running,it should put out from 13.5 to 15 volts. Any thing lower then that will tell you the system isn't charging properly.
SOME PEOPLE TAKE THINGS I SAY WAAAAAAAY TOO LITERALLY