How to "Decrease one on ea side every 4th row"

HELP! I don’t understand what i should do. The pattern reads:
“decrease one on each side every 4th row.” What does that mean? The first and last stitch?

It means to dec at the beg and end of the row. That doesn’t have to be the very end sts, many people prefer to increase one or 2 sts in so the edge sts are even for seaming.