Also watching the vid,
1) never work on a car supported by a widowmaker jack. Or any jack. Axle stands are a must.
2) the handbrake was stopping you car rolling, if your working on the back leave in gear, or ideal, chock the front wheels
3) the brake drum bolts/wheel locators are 12mm
4) the drum is cast iron, if your going to hammer it use a smaller hammer, big hammer +cast = cracks, and I've seen it done
5) if you look thru the wheel bolt holes, you'll see the adjuster. Back it off, drum will need minimal persuading
6) cable adjustment, on this side at least, is fine. Can see its on its stop
View attachment 169635
7) you didn't readjust the shoes, the knurled winder on the threaded bar. It want to be wound so the shoes are just kissing the inside of the drum.
My advise, buy some brake cleaner, take the drum back off and clean all the dust away. Where the shoes touch the backplate, pull the shoe away slightly and apply some appropriate grease (copper grease is perfect) if you get any on the friction material, clean it up. Use a bit of emery cloth to rough up the face of the shoes, and make sure the inside of the drum is clean and rust free. Make sure the adjuster is freely moving, put the drum back on and thru a bolt hole adjust it till the drum goes tight. Back it off a few clicks, til it's just free, and repeat on other side. As I said, the adjuster underneath the car is for setting the free play in the handle (no more than 1/2") and with both sides adjusted properly you should have 3-5 clicks on the handbrake