I don't see the equilibrium that you are referring to...but ICE, also referred to as RICE table is a way of outlining a chemical reaction in order to determine the equation for equilibrium.
This will be the reaction that you are presented with
I: Initial concentrations
Under each reactant and product, place the concentrations that you are given. If there is no concentration supplied, put 0.
Here you can use a variable (x) to indicate whether an amount is being added or subtracted.
Bring all the prior factors together into an equation to solve for your variables/equilibrium constant.