What does purl in the bridge & slip stitch mean?

How-to Questions
1

Hello, I am knitting this http://www.ravelry.com/patterns/library/chimera

it is my first time knitting cables and I am doing very well so far! I have just come to a road block.
When you look at the pattern there are two green sections
in one row you are to
" slip stitch with yarn held in front"(sl wyif) which I assume is just slipping knitwise with the yarn in front
on the next row just above this slip stitch it says
" purl into the bridge & slip stitch"(pu&p)

I’m not sure what the bridge means,
first I thought it was the yarn between the stitches. But if you purl that and then slip the next stitch it would increase. and I think that would throw the pattern off.
Please help!, MMM

2

When you slip a stitch, you do it purlwise unless it’s a decrease or the pattern says otherwise. This doesn’t make an increase, but I think you’re to purl the strand of yarn and the slipped st together.

3

thanks so much