Ok that is the only move you need to solve the center layer. There are some more moves that will make it faster in the extra algorithms page. But we are trying to use as few moves as possible, seven to be exact.
If you could not find an edge peace on the bottom layer then just do the move above and the cubelet that is in the center layer will the be on the bottom.
Now if the cubelet went to the correct place but is backwards then do the move again and then realign as was first stated and do it one more time. Your rubik's cube should now look like the picture below. So move on to the bottom layer section located in the links on the left hand side of this page.