Downloadable Content missing?

OK - this is going to sound like a really newbie question....

From reading the boards I see references to Korea, Incans, Polynesia and other Civs that are not in my list to play.

I was given Civ 5 years ago (about 4), then was given the expansions last year. I have installed G+K and BNW from CDs.

My civ list still seems shorter than others. Should I have downloaded further content from steam or something?

If so, how?

Thanks

If you browse the Steam store page for Civ V, you will see a bunch of DLC. You will also see Civ V Complete, which includes all of the DLC (except the latest scrambled maps pack) and both expansions -- even though you already own both expansions, that may be cheaper than buying the missing DLCs individually. And, as usual, shop around and be on the look-out for Steam sales.

Thanks very much - I'll give it a try.