Hey,
So are you wanting to be able to specify the cell name (like A5), and then pass values to it? Here is a community example that mostly achieves this:
https://decibel.ni.com/content/docs/DOC-2081
This example writes to the active cell that the user chooses. If this is not the exact functionality you are looking for, you can at least see how to use ActiveX to control different aspects excel and tweak the program to your needs. I hope this helps!
-Nathan H
Software Developer
National Instruments