Daniu answered this question from another thread. Short answer, it's not possible to "move" anything outside its own array. If there are multiple entries within the same array, then simply type the number you want it to move to (0 to move to the top, 1 for the second row, 2 the third, etc, provided there are those rows in that entry).
Re: EditSF 1.1 - Added Array Editing
Originally Posted by SilkZither 
Is it possible to create new entries
You can create new entries by using "Duplicate", then edit the duplicate. Reason for not providing a "New from scratch" is that you'd have to build the entire substructure correctly, and that is very error-prone. I'd be swamped in "why does this not work" questions I can't answer.
or move an existing one from one unit_array to another?
No, you can't move an entry from one existing array to another. Reason is that if it were possible, I'd have to enable it between all "array types", i.e. also from unit_array to armies_array for example - again, this would destroy consistency.
How do you use the "move" function from right-clicking the mouse?
The "move" works within the same array only (because there all entries are of the same type). You enter the array index to which you want to move the entry you selected and it will be moved there.