Welocme to Knitting Help!
On the odd rows you must have directions for making yarn overs, which increase the stitch number each time you do one and create a hole (very nice for lace knitting). On the even, purl rows the yarn overs will be closed up by purling through the back loop (tbl). Here's a video for purling the next stitch tbl but purling the yarn over tbl is similar. Every time you come to the yarn over from the previous row, do the purl tbl into the yarn over. You'll recognize it because it's a loop over the needle without a column of sts below it. Can you give a pattern link?