Hi, I'm a noob sorry but...

How do dlcs work? I mean, will you complete the game but get to keep going but it's starts the dlc quests?

No the ending is the same with the DLC's (battle at Hoover Dam) once you do that the game ends.

However there will be 4 (4 DLC's) locations where u can start the DLC in the Mojave. By entering those locations u can start the DLC. The other two DLC: Courier's stash and Gun Runner's Arsenal add equipment (mostly weaponry) to the game.

The four locations to enter the 4 DLC are in the far North (Honest Hearts; http://fallout.wikia.com/wiki/Northern_Passage), South (Old World Blues; http://fallout.wikia.com/wiki/Mojave_Drive-in), East (Dead Money, http://fallout.wikia.com/wiki/Abandoned_Brotherhood_of_Steel_bunker), and West (Lonesome Road; http://fallout.wikia.com/wiki/Canyon_wreckage).

You can only return to the Mojave at any time in the Lonesome Road DLC. The others require u to first finish the main quest before u can return to the Mojave. The only DLC you can not return to once finished is Dead Money.

You can play them when you want during the game, although most of them have strong suggestions on certain levels you should be before attempting them.

Before you finish the game, a Save file is created before the "no turning back" point. (as you likely know)
So you can use that save file to do the DLC, or use any existing character you have.

Yup and some say its best to do them in order I am not fully certain of the order but I think it goes, Dead Money, Broken Hearts, Old World Blues, Lonesome road. I Just got done with OWB and went to do a few quests and started broken hearts.

Honest hearts, sorry

The DLC's are additions, good ones even Dead money which I personally dislike. They are optional to do but very rewarding if you complete them.

Thanks! I'm aiming for Lonesome Road ;D