We have a working game. Now we can focus on making it look good - that is juice.
Select the Main Node and add a Node2D as child
Attach a new script to the Background
To get a checkerboard pattern, we look at the grid coordinates (X, Y).
If you add x + y, the result alternates between Even and Odd.
If the result is odd we paint that square colour A (Light Green)
If the result is even we paint that square colour B (Dark Green)
Add variables for the two colours
Also add variables for the
grid size and screen dimensions
Determine how many columns and rows there are
Loop through every column and row
Find where you are on the grid
If the cell position is even
If the cell position is odd
So that the grid is painted
Each time the game starts