You will need:
Roast...whatever size you want to use is fine, as long as it fits :) I usually do about a 2 lb roast for 3 people and some left overs. I've also done a 5 lb roast and it was the same cooking instructions...as for the type of roast...I've done several types and they all turn out great, so pick whatever type you enjoy.
1 box beef broth (or a couple cans of the beef consume)
3 cans cream of mushroom soup
2 onions cut into chunks
10-12 potatoes cut into thirds
10 carrots cut into fourths (you can do more carrots, they are SO good! as many as you have room for...)
Put it all in a roasting pan with a cover (probably don't have to keep it covered but that's how I did mine).
Cook for 4 hrs at 350 degrees. I think the low heat, the long cooking time and added moisture are what make it so good :) A couple people told me I should have added a box of onion soup mix...I'll try that next time. I figure the actual onion was enough onion for my own taste...but I'm sure the mix makes a great flavor if you want that.
oh yes, I added salt and pepper on top while cooking, lots of pepper cause I like spice...although it really wasn't spicy in the end.