Reading a Pattern

Hi, I was hoping that someone could help me read this part of a pattern. I am working on a Men’s Hat of K3,P3 but I am now at the shapeing of the top. The pattern calls for 1st row:
K2. (Sl1. K1. psso. Pat 13 sts. K2tog. K1. Sl1. K1. psso. Pat 19 sts. K2tog) K1) twice. K1. 79 sts. I understand how to sl1 and psso, but what confuses me is the pat 13sts and 19sts. As well as 79 sts I only casted on 87 sts. Can someone help me?
Also the next row it states: 2nd, 4th and 6th rows: Knit all knits sts and purl all purl sts as they appear.
What does this mean. Thanks for any help that anyone can
give this newbie that takes on a hard project for her third project *:aww: ***

When you work in pattern, or knit the knits and purl the purls as they face you, you just have to look at your knitting. If there is a knit stitch V on the left needle, knit it. If there is a purl bump on the left needle, purl it.

After you do the first decrease row, you should have 79 stitches left.

After you do the dec (sl, k, psso) work the next 13 or 19 sts in the rib pattern. If your next st is a knit, knit it; if it’s a purl, purl it. At the end of your decrease row there will be 79 sts left, you decreased 8.

For rows 2, 4,6 and 8 it’s what I said above - work the rib pattern, knit a st that looks like a knit, purl the st that looks like a purl.

Thank you so much to both of you for your help. I completely understand now! What a great way to learn to knit…