Well, the main events start with Sora, Donald, and Goofy setting off on their adventure. They visit worlds like the Kingdom of Corona from Tangled. In these worlds, they get involved in local problems that are also related to the overarching threat of Darkness. The encounters with Organization XIII members are significant events. Each encounter reveals more about their plans and the nature of the Darkness. Sora's growth as a keyblade wielder, learning new skills and techniques, is also an important part of the story. And the final battle to save all the worlds from Xehanort's evil plan is the climax of the main events in the full story.
In Kingdom Hearts 3, one of the main events is Sora's journey through worlds like Olympus Coliseum. Here, he faces powerful foes. Then there's the exploration of the new Disney worlds introduced in this game, like the world of Big Hero 6. Sora also has to deal with the machinations of Xehanort, who has a grand plan for the Kingdom Hearts universe. And throughout, his friendships with Donald, Goofy, and the Disney characters he meets are crucial in his fight against the forces of Darkness.
The main events include Sora's travels to different Disney worlds. He battles the Heartless and Organization XIII. Another important event is the search for power to defeat the Darkness. Also, the interactions with various Disney characters play a big role.