Her directions are correct: k3,p3 on row 1, p3, k3 on row 2. The rib pattern takes up 6 st. If you have a number that isn't divisible by 6, the row ends with k3. So to make a rib, the next row starts with a p3. It ends with p3 also, so you repeat the 1st row again and start with k3. There's only one st in knitting, one side is a knit, the other is a purl. So when you're doing ribbing you need work each st how it looks to you when you come to it. A lot of patterns read knit the knits and purl the purls as they face you; this is where knowing how to read your knitting comes in handy.