Purl decrease confusion

I am trying to make my first pair of mittens and I was doing pretty good until I got to this step it reads like this:
Top Shaping
Row 2
(Decrease row): P1, P2 tog, P 12, work Purl Decrease (abbreviated PD) as follows: P1, slip last st worked back onto left needle, slip second st on left needle over first st, slip completed st back onto right needle (PD made),P1, P2 tog, P 13, PD, P1. (32) sts.

OK now here come the hard part, I need to explain how I see this procedure and how I have been trying to work it and not having any success.

I am fine doing the P1 and the P2 tog but when I come to do the PD I mess something up. This is what I do…I do the P1, and when it says slip the last st worked back onto the left needle, do they mean the one that I just purled or the one to the right of that on my right hand needle? I have tried several different things here and none of them work. If any one has a better way of explaining how I should do this I would greatly appreciate it as I am on the verge of ripping out my already thinning hair!!! Thanks in advance! Victory…

They mean the one you JUST purled.

Purl a stitch… now it’s on your right needle.
Slip it back to your left needle without twisting it.
Then slip the stitch on your left needle just next to the stitch you just slipped (the one just to the left) up and over the slipped one… and off the needle.
Then slip the stitch back to the right needle and continue with the pattern.