Instructions
Learn about group or pack dynamics. Somewhat like their relative, the wolf, dogs have dominant members of the pack, usually an Alpha male and a dominant female. Everyone else more or less falls into line behind them. Dogs love order and predictability and as pack leader, they will look to you for it.
Keep toys picked up between play times so they don't become a source of conflict. Keep food bowls in separate areas of the room and monitor any dog that sees all the bowls as their bowl.
Consider having separate play/walk periods at least a couple of times a week, allowing each individual dog to have all your focus. Group play should be allowed daily with all willing members of the pack romping and vocalizing a bit. Be extra careful if you have a mix of small and large dogs, as the little ones can easily be injured by rambunctious, even though sweet-natured, big dogs.
Allow occasional scuffles between two dogs, which may be an attention-seeking behavior. You could actually make things worse by jumping in between them. However, if things escalate and there's a risk of the dogs hurting each other or you, you will need to intervene. Normally a spray of water in the face of both offenders works or at least gives you an opportunity to divert their attention or separate them for a few minutes. Try to avoid any type of scuffle between three dogs, as they will by nature choose sides and then you've got a real problem.
Try training each dog individually at first. Every dog should know how to walk with you without pulling on the leash and how to "sit," "stay," "be quiet" and "go lay down" upon your request. Once basic commands are learned by each dog, you can move on to a group training mode. You may need to acquire in-home services of a professional dog trainer to get the group thing going.
Provide each dog with an even amount of your attention and financial resources. They will all need food, water, attention and love, grooming, immunizations, monthly heartworm and pest preventative and regular veterinary care.
How to Handle Multiple Dog Households
The first thing to understand about handling a multiple dog household is that you have not simply gathered together two or more dogs to live with you. You have established a "pack" of dogs that has its own hierarchy, communications, benefits and challenges. For you to operate in your rightful spot within your pack, you will need to firmly, but not aggressively, establish yourself as the pack member in charge.