The K2, kfb, k to last 4 sts, kfb, K3 part is how every increase row will look, and you will repeat it on every 6th row, 5 times. So you will increase on row 1 (the initial increase row) then on 7, 13, 19, 25, 31. That will be a total of 12 stitches increased which will get you from your initial 74 stitches to the required 86 stitches.