Confusion w/ pattern

I am a new knitter and am TRYING to make a baby blanket on circular needles. I have a question in regards the pattern I am using.
My pattern indicates that:
Row 13 - K3P3K3 P9 then K9 P9 until the last 18 stitches, place maker then K9, K3P3K3
Row 14 P3K3P3 K9 then P9 K9 until the last 18 stitches, place maker then P9, P3K3P3
Okay so now I have 2 stitch markers on either ends of my blanket indicating where the last 18 stiches are.
Now the pattern says
Row 15 - Repeat Row 13
Row 16 - Repeat Row 14
Am I placing new stitch markers or just slip the existing markers?
The next two rows are the same as Row 13 & 14 but says slip marker (instead of placing marker)
Am I getting myself too worked up about the stitch markers and basically all I need to do is place/slip them as they are so that they indicate where my pattern does a change (ie P3K3P3 pr K3P3K3)

Please help me get piece of mind before I lose it!

Hi tdussell,

Just slip the markers. If rows 15 and 16 are identical to 13 and 14 and you added another stitch marker you would just have two slip markers at each end in the same spot. Only add a new marker if the location is different. When a pattern says slip marker it means move the marker from one needle to the other.

Welcome to the wonderful world of knitting.