I'm such a noob

[NocturnaSuppressio]

This may sound retarded, but I have played through the main quest 3 times, but never did any of the faction quests or side quests, this is my first playthrough where I do all that good stuff...... How the hell do I join the Dark-Brotherhood? Please forgive my Nooby-ness. Thanks in advance!

 

[Vegeta]

Google it man. But since you went through the trouble to post here... I don't know if you need to have the quest active or not (I always hear about it from Inn Keepers when you ask about rumors), but there is a boy named Aventus Arentino in Windhelm. Go into his house, where he is preforming the Black Sacrament and talk to him. That'll start a quest and after you do that quest, sleep in a bed and it should pick up from there.

 

[Uther Pundragon]

If you are new to TES, I would suggest making several different characters to use and role play with. This will allow you to spread out the guild and side quests while extending the life of Skyrim and making each character different and fun. But that is up to you.

To start the Dark Brotherhood quest line it is as Vegeta said. You may hear about a boy trying to perform the Black Sacrament in Windhelm. If you don't feel like waiting for this to come up via gossip then simply travel to Windhelm. This will allow you to hear about it a lot quicker.