When you finish knitting a row, the needle with the work is in your right hand. Then you pass it back to your left hand to start a new row. Each time a different side will be facing you - once the Right side and then the Wrong side. Usually
but not always, when knitting in stockinette - the right side is the knits and the wrong one is the purls. When instructions say "ending with a wrong side row" it means you need to do the wrong side row and then follow further instructions.
I hope it helps and i made it somehow understandable