2sts 6 times, 3 sts 5 times, 15 sts once-79 sts.
Knitting directions have their own language, but you'll become fluent quickly!
You need to cast on 2 stitches at the beginning of the row 6 times when you're at that edge; then 3 stitches 5 times when you're at that edge, and then 15 stitches one last time. When you're finished casting on all the stitches, you'll have 79 stitches total.
You can use any of the single strand cast ons in the videos.