Help with instructions on preemie garter stitch set

Hello Everyone. I am working on the Bernat Baby Set in size 3 mos. I just completed the sleeve and I am not sure I understand the next set of instructions.

Next row: (RS). Cast off 26 sts. K5 (5-[B]5[/B]-9-11-11) (including st on needle after cast off ). Turn. Leave rem 11 (13-[B]15[/B]-17-17-19) sts unworked.***

I got that part done so I have 20 stitches on my left handed needle and turned.

Back: 1st row: (WS). K5 (5-[B]5[/B]-9-11-11). K18 (20-[B]23[/B]-26-29-34) from left front st holder.
Knit 2 rows.

Okay, so I knit 5 on the wrong side as instructed. And, it was the first 5 on my left needle. Now it says K23 from left front st holder. So, does that mean leave the other 15 stitches still unworked? Was knitting those first 5 correct (I still have 20 stitches on my left needle). Where do I knit those 23 from exactly? I have my stitch marked and I also put a stitch holder in the side 23 stitches.

Sorry if this sounds all over the place. Guess I am just not sure what exactly to ask…

Thanks everyone!

Knit the 23 sts off the stitch holder and you’ll have 28 sts and the other 15 sts are left unworked for a while.

“Back: 1st row: (WS). K5 (5-[B]5[/B]-9-11-11). K18 (20-[B]23[/B]-26-29-34) from left front st holder.
Knit 2 rows.”

After knitting the sts from the st holder and then the ‘knit 2 rows’, you’re going to repeat the 4 row pattern that you used on the front. In the 3rd and 4th rows of that pattern, you’ll work across the 15 yoke sts that are held on the needle (43sts total).