Help with a chart


I have a problem understanding a knitting chart.
This is the link for my project:

There are k2tog sts in the chart, e.g. the k2tog on the 3rd row. Do I do the k2tog once at the end of the round or I do it every thirteen sts? The same on the 6th row. I only do the k2tog once at the beg of the round or not? The same on the 11th row,23rd, 25th and so on.

I would appreciate any help

Thank you

You should k2tog every 13sts on this round. In each of the rounds with k2tog, knit two together every repeat for that round.

Thank you very much.