From what I understand…after reading a bit. Take the dogs for a long walk together...I mean REEEEAAALLY long. Have them get to know their territory & tire them out. Once tired & they've made the association that they are now part of your pack the meeting will go smoother (hopefully). Allow them to meet & greet but keep an eye out for signals...threatening behavior like lots of lip licking, growls, teeth, etc. if need be just get in between them & stay calm. They will now how to calm each other & they will know how to communicate with each other.
GOOD LUCK & CONGRATS!!! 😃