97 Ford Explorer

Heater not working, replaced climate control swicthes, flushed radiator, checked fuses, hears my stupid question. Where is the heater core located, is there any fancy tricks getting it out, and is it worth going to a pick-and-pull to get the part(its 35.00 bucks cheaper but I dont no the hasle of taking it back out), anyway those are my questions, its my 18 yr. Olds car, shes going to college to be a nurse soon she can buy new, till then she thinks dad can fix anything.I work on my own harley thats about it, thanx for any info you can send me I do appriciate it and she will be warmer going to sckool and work, thanx Rick A.