I don't know if there is a video of someone doing seed stitch or not. But I can tell you how you can do it yourself so you can see how it is done. Put an odd number of stitches on your needle. I suggest only a few, like 7 maybe. Knit the first stitch, purl the next and repeat that sequence across. One thing that is important to remember when going from a knit to a purl is that you must move the yarn between the needles to front and back between each stitch. You must have the yarn in back when you knit and in front when you purl. If you forget to move it back and forth, it will make a mess. (Been there, done that. )
Work those 7 stitches k, p, k, p, k, p, k. Then turn to begin the next row. Since you knit the last stitch, the first stitch that faces you in the new row will look like a purl, knit it. (That is what they mean when they say knit the purl stitches.) Work this second row exactly as you worked the first row. K, p, k, p, k, p, k. With an odd number of stitches you will always begin with a knit and go in k1, p1 sequence across the row and you will be putting the knits over the purls and the purls over the knits.
As you do this small practice piece, use your powers of observation to notice what a purl looks like (the 1st stitch on the second and every following row, and every other stitch after that). The purl has a little bump right under the loop that goes over the needle. The knit stitches look different (the 2nd stitch on that second row, and every other stitch following that stitch). They have like a little vee under the loop on the needle. You will always knit the purls and purl the knits. In other words if you see the "purl" bump you knit the stitch. If you see the "knit" vee, you will purl the stitch.
If you were doing regular K1, P1 ribbing your would create it by always knitting the knits and purling the purls. It is really helpful to learn to identify the knits and purls from the way they present themselves on the left hand needle, ready to be worked. I described that above. Once you learn that, you can do seed stitch with an odd or even number of stitchs and just always knit the purls and purl the knits, without bothering to count or anything. The same for ribbing. You knit the knits and purl the purls to get the ribbing.
Use careful observation and you'll learn it quickly. I hope that helps.