You should create (if you don't already have one) a libraries directory in the directory where you save sketches. Then unzip the library to that new directory.
Also, it can help to turn on verbose mode for compilation (or uploading) depending upon which is causing problems. This can be done by selecting the Preferences option from the File Menu and clicking verbose compilation... See attached screen capture to illustrate.
Oh, after installing or changing a library you will need to restart (exit and come back) the Arduino IDE so that it will recognize the changes.
