Tubular Cast On

Hello Gurus…

Starting a shrug that involves a tubular cast on as the base for the back edge (it’s knit in one piece essentially, back to collar). Having a hard time with the pattern, which reads:

[COLOR=“Blue”]Cast on in scrap yarn using preferred method [COLOR=“Black”](calls for half the number req’d).[/COLOR] Switch to working yarn and do required 4 rows of tubular cast on.[/COLOR]

[COLOR=“blue”]First row: K1, yo, K1 repeat from * to * across, end K1
2nd row: K1, Sl1 P with yarn in front, move yarn to back, knit next stitch (yo of previous row), repeat from * to * across, end K1.
Repeat 2nd row 2 more times following sense of the ribbing.[/COLOR]

Problem is, I don’t know what to do when I start my third row…I am looking at what appear to be 2 “purls” (the knit yo and the K1). To keep the sense of the ribbing, while following this pattern, I’d be slipping those 2 “purls”, K1, etc… Will I slip the last “purl” at the end of the third row as well?
I am so confused, I’m ready to use one of the other tubular cast on methods I’ve read about. Here’s another question: if I use, say, the Italian method which involves casting on your required # of stitches right off, will this affect the end result significantly?

Attaching a photo of the garment, though it’s a dark colour and a bit hard to make out. Thank you so much, in advance…

You might want to practice this on about 20 sts or so to get the hang of it, but I think you just repeat row 2 twice more. That should give you purls and knits to establish the ribbing. You only slip 1 stitch pwise, then knit a stitch, slip a stitch, k 1, slip 1, all the way across. The next row, I think you’ll be slipping the st that was knit on the previous row (which will look like a purl on this row) and knitting the one that was slipped. Ignore the part about the knit YO, that’s just information to tell you which stitch is which on row 2, it doesn’t have anything to do with rows 3 and 4.