enlarge the given size of a baby blanket

I am knitting a baby blanket Blanketoliver but would like to make it longer and wider. Longer is an easy fix as I can just knit it longer, how do I go about altering the pattern to make it wider I.e. How do I work out how many extra stitches to cast on…

Welcome to KnittingHelp!
Is this the pattern?

You can count how many stitches in the bunny and the space between bunnies and increase by multiples of that number until you have the width you want.