I could tell you about my introduction experiences but I checked that link in the past and it's pretty good.
Sometimes is really easy, sometimes it takes longer and more work and patience, depending on the cats.
Try not to let them lose face each other since day one, but keep them in separate areas and let them be curious about each other and getting used to each other smell.
I'm so sorry about your kitty
I can relate
Well now you'll be saving a life and changing a kitty's world from the shelter <3