You can unzip the XLGTa workbook to your "My Documents" folder or other location of your choice, but *not* anywhere under \Program Files or any other restricted or protected folder.

Use of XLGTa requires that Excel macros be enabled.  When you open the workbook with Excel you must 1) enable editing and then 2) enable macros.

The first time you load a 1 degree step size file you'll see "Filling down more rows ..." in the Excel status bar area.  If you then save the workbook with those extra rows added you can avoid the additional wait in the future.  You should also save the workbook if you want to "remember" the most recent folders for reading pf3 and csv files or to save your path settings for 3D viewers.

Before using the "3D Plot" button please review section "Showing 3D plots" near the bottom of the XLGTa web page:
https://ac6la.com/xlgta.html

Dan Maguire, AC6LA