I’m with @wildpotato , that those big pumpkins that are grown specifically for Halloween Jack o lanterns are not the best pumpkins, flavor wise, for recipes.
But if you are bound and determined to use it, This Site will give you step by step instructions on how to make a pumpkin pie (although he/she also doesn’t recommend that kind of pumpkin if you want something really delicious).
If you want to prepare your pumpkin flesh into a puree, to freeze and use later Look Here
I love roasted pumpkin seeds, I don’t bother to try to take the shell/skin off of them. I just eat the whole thing. Here’s how to Roast Pumpkin Seeds I’ve never taken the extra step of boiling them in salted water before roasting them, but maybe I’ll try that method and see if they’re better.
But if you want to prepare them with the shell off you can try This Method
I love Pumpkin Bread
Pumpkin Soup would be fantastic at this time of year. If you want a vegetarian version, just use veggie broth instead of chicken broth. If you feel the urge to make you own fresh Vegetable Stock that might be fun, especially if you have some leftovers.
Hope this all turns out delicious!