Are your pumpkin plants ready to plant out? Harden them to the elements for a couple of nights first by leaving them outside in a sunny protected spot.
The fear of frost is now past. Plant your pumpkins in well prepared soil with plenty of well rotted organic matter added. Plant one metre apart, to the depth of the original soil level in the pot.
Water frequently. Feed with liquid feed weekly. Water the roots not the leaves!
Check your pumpkins, why not put down beer traps to prevent the little critters eating your plants.