Well, you can start in Mark 9 where 'hell-fire' is translated. Vs 49 states ALL SHALL BE SALTED WITH FIRE.
Of course, if you study, you'll find Jesus spoke of Gehenna, the burning dump outside Jerusalem.
If you think its 'literal', there should be people burning in a dump outside Jerusalem.
Ponder upon that and you'll see the foolishness of men's doctrines.