The squares are all sewn together. In the pic's you see the back and front. I joined them by single crochet all around and finished the edging with a contrasting black picot stitch.
Don't you love the little splash of color?
For the picot stitch: chain 3, double crochet in first chain from ch-3, skip 1 (or 2) stitch and join with a slip stitch. Super simple! And if you only skip one the only important thing is that you have an even number of stitches. In a square that's always the case...
Enjoy the holidays!