The final Skyrim act (Act 3) features seven main-quests that must be completed by those who wish to beat the game.
These quests are linked to each other, meaning that players will have to complete one main quest at a time, in order to advance in the game.
Our Elder Scrolls V: Skyrim walkthrough explains how to complete all quests included in the last act, pointing out all side-quests that may appear, all areas that should be visited and the characters that interfere with the players hero.
The first quest of the third act is The Fallen, which starts while visiting the Throat of the World.
Players will notice that several main-quests included in this act, will intersect, therefore, it is a good idea to maintain an order while playing this act.
After you defeat Alduin, get ready to start The Fallen main quest.