Sweet potatoe

We had a big discusion on growing sweet potatoe at the garden center yeasterday.People said buy one from the shop and chit it on the window sill in the glass vase used for hyacinths then plant in a tub in the greenhouse as they like sun and heat.
Others said you cant grow them they are to difficult.Also you dont plant the chitted tatty but the shoots.They grow huge etc etc
Has anyone tryed these and succeeded?Any info would help as we are keen to try if poss