what does p o(1,0) mean?

It's from a pattern for baby mittens and I've looked everywhere.  Any ideas would be soooo great.

many thanks.

p for purl stitch, the numbers are related to the sizes.  For example, if the sizes were small, medium and large, in the small pattern, you would not purl any stitches and would move on to the next written stitch, in the medium size, you would purl one stitch and then move to the next written stitch, in the large size, you do not purl any stitches and would move on to the next stitch.

Oh thank you very much.  None of the ladies at the craft store thought it was actually a zero.  :)