In Doric temples, the columns have no base, but just sit right on the floor. At the top of the columns, there's a capital made of a sort of small pillow in stone, and then a square block, under the architrave. On the architrave, there are triglyphs and metopes.
To find out more about Greek architectural orders, check out these books on Amazon or in your library:
Ancient Greek Architects at Work, by J. J. Coulton (1982). An interesting look at how Greek architects worked.
Greek Architecture, by A. W. Lawrence, R. A. Tomlinson (5th edition 1996). Might be a bit out of date.