Border and Color Change

I am trying to figure out how to make a border on a striped blanket. I want to purl first stitch for the border and knit last stitch. I am at purl first stitch and I also want to change colors. I can’t figure out how to do both in my new color.

You can hold a tail of the new yarn along side of the left needle and held in place with the left hand. Another way is to loosely tie the old and new yarns together and start to purl that first stitch. The yarns can be untied later and the ends woven in.

Ok. Thank you so much!