When a pattern tells you that there is a repeat of 11 plus 13 it means that the actual pattern is created by those 11 stitches. The 13 are "supporting actors" if you will.. they sometimes form the border or in between the sections of pattern. Somewhere on your pattern it should give you the pattern detail.
Also see the next excerpt:
Row 4: (RS)k1,ssk,k3 yo,k1, yo, k3, k2otog, ssk, k3, yo, k1, repeat to last 6 sts, end yo, k3, k2tog, slip1.
Can somebody break that down for me? Specifically, which part do I repeat (before **, between **, all of row 4???)?
On Row 4 you do the part before the * once. Then you repeat the portions between the * till the last 6 stitches and then you do that last bit on them. So the part that is red you will repeat several times till you have 6 stitches left. Then you do the last bit.
Row 4: (RS)k1,ssk,k3 yo,k1, [COLOR=Red]yo, k3, k2otog, ssk, k3, yo, k1,[/COLOR] repeat to last 6 sts, end yo, k3, k2tog, slip1.