This guide instructs you on how to download and use the popular ' Marriable Serana' mod by C0drm0nk33. The only way to marry Serana or any other vampire is through the use of a mod. Skyrim doesn't actually allow you to marry any vampires through regular in-game actions.
Should you need help on anything else Skyrim-related, make sure to head over to our Skyrim tips and tricks guides hub, featuring a wealth of articles on how to start out the game, as well as where to head first after you're let loose in the open world.