double knit hot pad Heart from kntting help

[Dotiintn]

Hi I am trying to work the double knit hot pad with the heart from knitting help.
I understand the double knit but the chart had 29 sqs and the cast one is 60 wich would equal 30 stitches. In the first stich you slip, I beleive that is the first two cast ons and at the end you purl the last and I also beieve that is the last two cast ons. I am lost as to what is not worked. when you start the row 2 (most red) is the slip stitch the first square on the chart or do you still work it?
Help Please... Thanks Doti