"You take 10 stitches off each side, and thats for your underarm," - yes, that part is fairly clear, it's the sts for the undearm.
"then you have to increase 30 stitches and then net 1 pearl, 1 for 2 inches and then it has to go around." This part isn't so clear.
Is she knitting it top down, bottom up, what? If we could have the name of the sweater or exactly what the pattern says, with a little more detail on how it's constructed, it would be helpful. Sometimes people post a summary of what they think it says and it comes out just as confusing for other people.