One main strategy for getting words to agree with a noun, is to make sure features are assigned to the noun and then in the transfer rules make the needed adjustment to the words you output depending on what the feature values (or class values) are. You can use the Rule Assistant to do this. See Section 4.7 of the help documentation.
If you can't use the Rule Assistant for some reason and you want to see how to do this ‘manually’ in a sample language pair, please watch this video.
If you would like to try creating the rules along with the video, please follow the instructions in the file: Readme.txt in the FLExTrans\FLExTrans Documentation\Agreement folder. See the file transfer_rules - solution.t1x which shows the form of the rules shown in the video.