Welcome to Knitting Help. To go from 8 stitches to 16, you have to have 2 sts for every one of the 8. You will yo, k1 in each stitch. Notice the where the * is. It means to repeat the yo, k1 all the way around. It' the same as if it said, repeat from *.
Happiness is catching that dropped stitch while it's still fixable..