HELP!!!! casting on?

[Mirthy]

Im making armholes on a dog sweater... and

How do you cast on 6sts after you've p3?
my pattern reads

p3,cast on 6 sts , p to bind off sts, cast on 6 sts?

What does this mean?
how will this end the armholes? and I need HELP!!

[suzeeq]

Purl 3 sts, then put your right needle in your left hand, use the knit or cable cast on (see the cast on videos here for how to do them), then put the needle back in your right hand. Purl across your work to where the next bound off sts are, and do the same thing.

[Simply_Renee]

You could also do a backward loop cast on, but it's a little trickier to knit from easily.

Just keep going- it's pretty clever how this will make an armhole but you'll see!