Start with the frozen bacon - I use frozen because it is a little hard to chop thawed bacon into 1 inch squares. Give good sized Chucks of thick cut bacon in 1 x 1 bits. Don't worry that its frozen.
In a large stock pot over medium heat - toss in all the bacon, and start cooking it down. Have no fear of burning the bacon or over cooking it, using frozen helps with this as well.
You're looking for Cooked bacon chunks, not bacon crumbles.
Leave all bacon and drippings in pan.
While cooking the Bacon start breaking down your beans. I like to snap off both ends, and leave them whole. If you need to cook this a little faster you can break them down into one inch sections of beans(just be careful they don't start falling apart!).
Put half of the butter into the pan and add the assorted beans. At this point you can add a little water to the mix just to get some extra steam going in the pan and help cook your beans.
If you've cooked with bean before then you might know what to look for, but otherwise, Beans will turn a much Brighter color when they are cooked, but still have that nice texture. After that point they will start turning darker and softer. So this is where it is left up to the Chef. I like mine to have a bit of that nice texture so they're not falling apart when I try to load up my fork.
When cooked to desired texture add remaining butter, and mix with beans to give a fresh coating. Your bacon should be just about to start falling apart at this point.
MIX IT UP!
This is just the basics, I've done this with added minced Garlic, fresh pepper corns, used chicken broth or beef broth, and even added Asparagus to the mix. It's a great side to any meal.