I've just gone to Steam headquarters and I have Dead Money and the others "installed" but how do I get them listed under Quests so I can go and do them?

Currently I have Sierra Madre, Happy Trails, Hard Luck Blues, The Reunion, and Midnight Science Fiction.

Those are the DLC quests. XD

Sierra Madre Grand Opening is Dead Money

Happy Trails is Honest Hearts

Midnight Science Fiction is Old World Blues

The Reunion is Lonesome Road

Hard Luck Blues is just a base game side quest, unrelated to the DLCs.

I feel a little dopey now. But at the same time how would I have ever known that? Thanks a lot.

When you start a new character, you are spammed with DLC messages as soon as you leave Doc Mitchell's house, then you would have seen the quest added. If you install the DLCs after you started the game, it should still show you the DLC messages, which include adding these quests, but most people seem to ignore those. I know I do.

Yes, I recall the "spamming" now. But I guess I was so preoccupied with getting on with things I didn't pay attention. Thanks for the answers, folks.

Just be careful, other than Honest Hearts (which you can do at a fairly low level), all of them are meant for high-leveled characters.

What's the idea there? You do them after the main quest? I have another question: do I have to lose my companions in every one of them?

You can't do them after the main quest, completing the main quest ends the game. Yes, you can't take companions into each DLC.

I would also be careful about taking high-level characters into the DLCs. The enemies scale up after level 30, 40 and 50(at least I think this is accurate).

IMO Honest Hearts isn't bad after level 10, OWB and LR maybe wait until level 20. Dead Money is the wild card, it is about equally difficult no matter what your level.

Also, while you can do Honest Hearts at pretty much any time, there is a sort of intertwining story behind the rest of the DLCs. If I recall, the general recommended order to do them in is Dead Money, OWB then Lonesome Road last. Although I know I've seen a lot of people say they switched around DM and OWB without issue.

I have a habit of using Dead Money to build characters, and I often do it at a very low level, but I would not advise this on a first run of the DLC.

Honest Hearts as mentioned can be done at any level. Dead Money, Old World Blues, and the Lonesome Road do have an overarching back story, I usually do the last three in order anymore.

EDIT Dead Money, Old World Blues, and the Lonesome Road automaticly dismiss Companions. Honest Hearts I always need to manually dismiss any Companions.