This is a standard subVI call.
Just code up the "popup" that you want, make it a dialog (front panel visible when called), with all the inputs for the data you want to pass, and then drop it into your main VI. Then, to call, just wire it into a case of some sort that comes up when the user clicks the button.
If you look at the Basics section of the Examples that ship with LabVIEW, there should be something on calling subVIs with their front panels visible.
Also, I recommend getting "LabVIEW for Everyone". It's a great book for beginners. Also, take (or get the CDs for) the LabVIEW Basics I and II courses. These are essential for learning LabVIEW.