If you have never tried Sew-as-you-go, please take time to try the technique. Not only is it good for joining panels, you will find many other uses. Often socks knit on the flatbed knitting machine are seamed using this method.
It's a neat, attractive, strong seam, that SAVES TIME!
Follow the video as you are practicing. Use light color yarn (and contrasting colors if possible) so you can see the formation of the sew-as-you-go stitches.
Swatch 1:
Knit a small swatch or use the edge of a previously knit swatch for this sample.
Swatch 2:

Cast on a new swatch
On the side opposite the carriage pick up and hang the cast on edge stitch of Swatch 1. Be sure to have the Private/wrong side of Swatch 1 facing you. (purl side facing on both pieces)
Be sure to hang the stitch from swatch one ON THE SAME NEEDLE as the end needle of Swatch 2. Don't increase, double up the stitches as you join to create the seam.
To reduce bulk, pick up a single strand (one leg) of the edge stitch
Knit across and back (carriage is on the opposite side of the seam)
Continue picking up stitches from Swatch 1 as you knit Swatch 2

TIP:
Placing yarn markers at regular intervals can be helpful in seaming with any method. For example, as you are knitting the first piece place a yarn marker along the edges every 10, 20 or 25 rows (whatever interval you will remember).
As you knit the second piece and sew-as-you-go, the markers will help you match the rows of both pieces perfectly.<br>