There are a few ways to cook this, depending on how fast you want to cook it.
I normally place it into a preheated oven around 10-11pm, at 250...yes 250 degrees, and cook it all night long. When we wake up I open the last can of soup and mix it with a wisk with about a cup of water. I pour it on top of everything and put it back in the oven. I then turn the oven up to 350-375 for about 45 min. and then turn the oven off. I let it sit in the oven for at least another 45 min.- 1 hour while preparing everything that we will eat with it. This will fall apart in your mouth!
If the soup doesn't make a thick enough gravy you can remove everything from the pan, except the juices. Add some flour and wisk over heat to thicken. Water can be added if it gets too thick.
Alternate cooking method:
If you don't have all night to cook it you can cook it for 4-6 hours at 350-375.