Unlock the Monsters, Inc. Realm in Dream Castle
Enter the Monsters, Inc. Realm
Complete the early Realm quests to meet Sulley and Mike
Progress the Monsters, Inc. friendship questline
Unlock and complete the quest that brings Sally to the Valley
Gather the required quest items when prompted
Place Sally’s house in the Valley
Pay the required Star Coins to build her house
Wait for construction to finish
Speak to Sally to welcome her to the Valley