IF they can't wait do they need to advance to the first round. I want good answers long or short. I want them long, but it's your choice.
At first, your dog will not accept the newcomer. So let get to know each other. Maybe you have a way of keeping them away from physical contact while letting them see each other. Like the new dog could be in a room behind a glass door/wall or a screen door. After a few days, the dogs should be comfortable with each other. And you can let them loose, but always supervise them at first. You wouldn't want them to fight over their territory. Pay more attention to your male dog. And not as much attention to the new one. Because if you give each the same amount of attention, this will result in a fight to see which is beta. (Cuz you're alpha)
If you may try to blast it clean.
There are key pad lock sets available for house entry doors that should work the way you want. Many places carry them. Home Depot and Lowes both do. I'm pretty sure they can be programmed to relock automatically. Anyway you can always ask at the store.
