Help With a Variable Issue

Hello! i'm currently trying to config Yanfly's Input Combo Skills (this is sort of irrelevant). The purpose is basically to change the max allowed commands be equal to the AGI of the character who is selected or attacking.

Simply : I'm attempting to make a variable that finds the attacking/selected party member's stat of a certain kind. 

I simply want a script that finds the stat, puts it in an integer variable.

It's a real simple problem I think but I can't seem to find a way to script it.

Thank you in advance!

Control Variables > Game Data > Actor

Thanks Shaz, 
The problem is I want this variable to change depending on the stat of who is attacking, is that possible, or will that require some tweaking of the script to change how it's set up?

In your damage formula:

where id is the variable id, 6 is the parameter id for agility (change to 0-mhp, 1-mmp, 2-atk, 3-def, 4-mat, 5-mdf, 6-agi, 7-luk), and put the actual damage formula after the ;