Very useful illustration of the basics.
Not wanting to take away anything from someone volunteering to show a technique but there are a couple of features that might be worth pointing out.
Poor practice to put any poison in a food container. Recycle something non food from the garage if you need a container, hack the bottom off a bottle if you have nothing else. Make it obvious it's not drinkable, do not use a coffee cup.
The chap announces 7 seams on the third hive, translates that to 35ml of solution. Then as far as I can count he treats 6 seams. Fair enough in the real world where a miscount or change of mind occurs and an extra 5 ml over six seams is not going to overdose but not a good example.
No insulation visible and crown board holes open. No mention of the floor type but a minority practice to leave holes over the centre as far as I read this board. Most books have warnings about taking queen excluders out if over wintering on multiple boxes, two are present here but late in the season to take them out I would have thought.