Your pot looks a bit small, but may work if you move the other guys sharing, and feed regularly. The vines get really long so your pumpkins would be resting on the gravel or concrete which is fine, just turn them every few days. Decide on just a few to keep and remove the rest once you can see the little ones. If you have bees they'll take care of pollinating or you can help nature along with a soft brush, lots of how to tips on the internet.
I love to carve names or pictures on my pumpkins when they're young and soft, as they grow the carvings scar over and are great fun.

They are pretty easy to grow. The flowers produced are both male and female so all you need are bees or you can hand pollinate.

I’ve seen people rig up nets to hold the fruit in patio gardens.

and in Farmer Boy they grew a giant pumpkin. They chose the best little pumpkin on the vine, made a tiny cut into the vine, put a bowl of milk under it and put a wick into the milk and the other end into the little cut/slit. The pumkin drank it up and they did this for months until it was so big that in won a contest for the largest one.