Keep the cats separated at first
Exchange bedding or toys so they can smell each other
Feed them on opposite sides of a closed door
Let them hear and smell each other before face-to-face contact
Use a baby gate or cracked door for visual introductions
Keep initial meetings short and calm
Supervise all first interactions
Provide separate food, water, litter boxes, and resting areas
Reward calm behavior with treats or praise
Do not force interaction
Separate them again if either cat shows stress or aggression
Increase contact time gradually
Allow each cat to retreat to a safe space
Repeat introductions over several days or weeks as needed