THE BASE : (this step works best on a flat surface) for this you will need a lot of flat pieces (like in second pic)
lay them out to form a square, mine was 10x10 inches (the squares were as big as four square pieces)
the result should look something like this (see 3rd pic)
then just connect the flat pieces together using normally shaped random Lego pieces (you can do a border if you want, mine was green) the last pic shows the completed base with a border.
Step 1: The checkered squares
(I recommend doing this step on a flat surface)
Take a bunch of normally shaped black and white(or blue and red :) legos,and form them into squares. (they should be as big as four square pieces) there should be 64 squares.
then just connect them to the base like so. ( alternating colors)