As with many of Bethesda's huge adventures, Skyrim was treated to a series of hefty expansions that introduced new questlines, weapons, factions, locations and even the ability to build your own house.
If you're playing the original versions of the game and have bought the DLC, it'll show up on the game's main menu to signify it's available. If you have bought the PS4, Xbox One or PC version of the Special Edition, it'll automatically be included too.
How to start Dawnguard DLC in Skyrim
To get the ball rolling on Dawnguard, talk to common guards that roam inside or surrounding major cities, and they should tell you about the Dawnguard faction. From there, you'll get the 'Dawnguard' quest unlocked, with a mission marker that guides you to a cave (Dayspring Canyon) before heading to Fort Dawnguard, where you speak someone inside to start 'Awakening' and the DLC proper.
If you can't find one of the above guards to trigger the location, it's said you can just go straight to the Keep and start chatting to those inside to start anyway. To make your way to Fort Dawnguard, following the directions in the following video by OfficialBackend:
How to start Hearthfire DLC in Skyrim
Hearthfire isn't a traditional story-driven expansion, instead adding the ability to own plots of land, alongside other smaller additions across the game (including adoption).
In order to access the meat of the DLC - building your own homes - then you must visit specific Jarls and complete quests to unlock them. Our Skyrim House page will break down how to unlock each plot of land.
Want more help with Skyrim? Find out how to join every guild and faction, how to earn Gold fast, level every Skyrim skill to 100, max Crafting skills, max Warrior skills, max Thief skills and max Mage skills, how to get married, where to buy a house, the best weapons ranked, the best armor ranked, how to start Dawnguard, Hearthfire and Dragonborn expansions, use console commands on PC, and read about what's new in the re-release with our Skyrim remastered guide, including how to install mods in PS4, Xbox One and PC's Special Edition.
How to start Dragonborn DLC in Skyrim
Play the main story past 'The Way of the Voice' (where you climb up the Throat of the World) and then visit a major city. You should see cultists walking around, who will ask you if you're the Dragonborn.
After the conversation, they should fight you. Check their bodies for orders that direct you to Windhelm docks. Once there, find Gjalund Salt-Sage on boat 'The Northern Maiden' and ask him to take you to Solstheim.
He'll refuse initially, so try the various options available until he agrees to take you the island to begin the DLC. Here is OutsideXbox with some finer details of the journey:
Of course, this page simply has what you need to start each expansion, with each quest spinning out to a number of main and side-quests and encounters, the details of which we'd rather not spoil. As with anything else in the game, you're free to put them off or pursue them whenever you like - the choice is yours!