Please help with this pattern

Hello! I am currently working on a scarf that uses four different colors, and each color section is a different stitch pattern. I’m a little confused by the pattern for the section that I am on and any help would be appreciated.

Here is the whole pattern for this section(with 41 stitches cast on):
Rows 1-2: K
Row 3: k1, (sl1 pwise, k1) to end
Row 4: k1, (yfwd, sl 1 pwise, yb, k1) to end
Rows 5-6: K
Row 7: k2, (sl 1 pwise, k1) to last st, k1
Row 8: K2, (yfwd, sl 1 pwise, yb, k1) to last st, k1
Rep rows 1-8 three more times
Rep rows 1-6 once more

Here is where I am lost:
Row 4: k1, (yfwd, sl 1 pwise, yb, k1) to end.

I understand what “yfwd” means, but am I supposed to go ahead and knit a stitch after the yfwd and before the slipped stitch? If not, I really don"t understand how row 4 is different from row 3, unless I should be keeping the yarn in back when I slip pwise? And if I am supposed to knit 1, I realize that it will add an extra stitch, but I don’t see where in the pattern those stitches are decreased so that I maintain my 41 cast on stitches. This is a UK pattern, I don’t know if that makes a difference.

The yarn forward, slip stitch, yarn back makes a decorative bar across that side of the work. I can’t tell for sure which is supposed to be the right side. In either case, you’ll have a gathered-looking, very thick strip where rows 3 and 4 are, surrounded by bands of garter stitch.

Neither the yarn forward nor the yarn back uses a stitch. You knit the first stitch in the row, then do the (yf-sl-yb k1) across. You won’t increase or decrease by doing that. If you can’t picture it, just do exactly what the pattern says.