Alrighty, let's walk through this.
You will have just finished your stockinette stitch part, ending having worked a WS (purl) row. Now you have the right side of your work facing for your next row.
On this row, you will decrease one stitch at each edge. It is recommended to not do a decrease at the very edge because it makes it a bit more difficult for seaming, so what I always do is put the decrease one stitch in from the edge. So you would K1, K2tog, knit to the last 3 stitches, K2tog, K1. So there, you have a decrease on each side of that row.
So the every 6th row 4 times, and every 4th row 2 times part. If the decrease row that you've just worked were called row 1, for sake of our discussion here, repeating the decrease row every 6th row 4 times would be on rows 7, 13, 19, and 25. Then decreasing every 4th row 2 times from there would be on rows 29 and 33.
So in total you have 7 decrease rows, and are decreasing two stitches on EACH of those rows (one at the beginning and one at the end) which is a total of 14 stitches decreased. Taken off your 41 original stitches, it leaves you with 27 stitches just as your pattern says.
Hope this has been helpful, shout back if you need more help! :XX: