I have rent income in Germany, which I filed in the US. I heard I should have filed in GER and here only file the tax I paid there. Where I can I enter taxes paid abroad?

I have rent income in Germany. For 2014, I filed that income in the US with my normal tax declaration. Now I learned I should have filed that income in Germany, and in the US only mention / file the tax that I paid over there, as part of the double taxation agreement between Germany and the US. In order to avoid double taxation, I probably now need to amend my US tax declaration for 2014. Can you confirm that this is right, and if so, where I can enter taxes paid abroad?