Start by clicking on the Load button in the Curve Window. This brings up the Curves load file dialog, which behaves exacly like any other open file dialog, with one important addition: the Curves load file dialog allows you to click on each of your curve files in order to see what they do to your particular image. This is a great time saver.

To use this feature, simply click on a particular acv file, and note the effect that it has on the image preview. To see all of the channels of each curve, click on the "All" tab before opening a curve file.

The increased efficienty of this feature is particularly useful because of the Curves auto-save feature, which creates a new curve file every time you change an image. The same goes for the the Favorites feature, which allows you to catalog curve files that you and others have contributed.