I didn't find a video, but what I do is lift the bar between the stitches from back to front with the left tip and then purl into the loop in the front.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry