The pattern says to pick up 3 stitches/4 rows along. I do not understand.
I'm assuming you are making front bands. From what I understand the pattern tells us to pick up 3 sts along the edge per every 4 rows of the sweater. So, we have to skip a row in order to make it 3 sts. this until you reach the last stitch st. where you want to end the band.
Here are some videos that I think they might be helpful to you and give you a better understanding than me explaining it.