Arg, need knitting help

[B+EBabyDipes]

Hello,
My name is Carly and I started knitting in the beginning of December! I am totally ADDICTED!!!

So I've made a few things and am now attempting a sweater....

Here's where I'm stuck;
I have begun to shape in the sleeves which are attached to the back. Then is says "Divide for fronts" Huh? Then it says, "next row k48 sts, leave those sts on a spare needle, cast off next 21 sts, k to end" more Huh??? Then come, "cast on last set of 48 sts only for left front. Work further 25rows ending at sleeve edge"

Any help would be appreciated!

Thanks in advance!
Carly