I probably did it my own way, instead of the instructions. Generally follow the instructions, of course! But for your info, here's the "rule" on how to slip, generally:
If it doesn't specify, slip it purlwise, UNLESS it's a decrease, then slip it knit-wise.
This is what Vogue Knitting says, and I've found the rule to be a great one.
I'm also in the habit of slipping the first stitch at the beginning of any row. I slip purlwise on the purl rows, and knitwise on the knit rows. I'm sure you could do it differently with fine results, but I read once that this is a good way, and I like it, so now it's habit.