sleeve increase

Hi can anyone help me please.? I have this pattern, which I’ve done the back on the sides of but I’m struggling with the sleeves. The pattern requires an increase of 2 stitches but the pattern itself is in multiples of 3 stitches. Surely this will mess my pattern up? Can anyone help me in plain English how to get this increase to fit the pattern? Here is the link

Many thanks in advance.

Incorporate the increased stitches into the pattern as you can. I usually increase as a knit stitch and then on the next row, work the stitch in pattern. You have p2k1 repeats for example so the first increase becomes a purl stitch. The next time you increase is also as a purl. The third increase is as a knit and so on. You won’t necessarily have enough sts for a full pattern repeat at the ends of the rows. The important thing is to maintain the columns of knits and purls that you have established in previous rows.