How do you use crop presets?

[14thstate]

This feels like an incredibly stupid problem, but I cannot for the life of me figure out how to use the crop presets. I've tried clicking on them, double-clicking, hitting enter, clicking the image, right-clicking, dragging the preset name onto the image (doesn't seem to register as being dragged), creating the crop box first and then trying to add a preset (it won't let you), and clearing out the whole thing and starting over.

I'm using CS5, and I'm working with a flat JPG on which I've made manual crops, as usual. But I've got to crop it to a specific size to fit a frame, so I figured it would be easier to use the presets, which I assume give you a crop box of that size that you can then position on the image as desired.

I've found a bunch of posts about crop presets, but most are just about what they are or how to make them - none explicitly tell you how to use them. So I'm guessing it must be something super simple that I'm missing. Thanks so much for your help!

[14thstate]

Clarification to my question: I do see how the crop box stretches proportionally when you drag it, but what I'm wondering is whether there's a way to drop a dimensional crop box right onto the original image. This image is something I've already enlarged and resampled, and I don't how much further it can go and still look good.