Help to make this a little larger

I would like to know if anyone can tell me how to figure out the multiple on this pattern, or how to make it a few inches larger:

You’d like to make it a few inches wider? This pattern row:
Knit 8, (purl 8, knit 4) 9 times, purl 8, knit 8
indicates that you can increase in multiples of 12. So you could
Knit 8, (purl 8, knit 4) 10 times (or as many times as you would like), purl 8, knit 8.