A couple of suggestions, if y'all don't mind. Been building my own hydraulic lines for my bikes for quite some time and found one or two ways to make the job easier. The video shows them cutting the braided hose with a cutoff wheel. That's fine, but if all you have is a hacksaw, you can do the same thing.
If you wrap the braided line where you plan to cut it with either ordinary electrical tape or duct tape, you won't fray the steel lines. If you put the locking nut (the part that stays on the outside of the line) on over the smooth, unfrazzled end of the hose before you begin any cutting, it'll save you some aggravation.
The smaller ferrule that goes inside the locking nut should fit between the braided steel of the line and the soft inner liner of the tubing. No steel threads on the inside. Be sure to seat the ferrule completely so it won't leak. There's a small lip on the inside of the ferrule that seats against the inside part of the tubing. You can tap the ferrule into place with a screwdriver handle or a pair of pliers and you'll feel it seat.
Slip the locking nut up over the ferrule, screw in the fitting the forms the end of the completed hose and Bob's your uncle, as they say.
Braided lines make a huge difference in the feel of brakes and go a long way toward firming up most spongy feeling brakes.
Oh, yeah, sourcing of parts. Earl's makes high quality stuff and high prices. If you're lucky enough to have a hot rod shop in your town or a auto race shop of some sort, you can often buy the hose and fittings cheaper and you can often kind of mock up what you're doing right there, so you know what angle fittings to get.
YYMV, Others may differ, Take all advice with a grain of salt.