Looking at the Banks kit (1st image) then it's the same principles as the home made kits we've seen.
As Stephen says, everything from the old brakes comes off, including the hub. The caliper mounting brackets go directly on to the radius arm and are held in place by bolting into the aluminium hub carrier/upright. I had to use longer bolts to allow for the added thickness of the extra bracket, and looking at the Banks kit, they may have supplied new bolts for this part.
The bracket mounts like the second image. Then you fit the spacer & hub to the splined driveshaft, bolt it all together.
The disc slips over the hub using the wheel studs, just as the brake drum does and is held in place when you put the wheels on. I can't tell if there's a securing screw in the Banks kit to hold the disc in place when the wheel is off, for example changing pads, etc, but there probably will be. The discs look to have been re-drilled from something else so it's just a case of deciding which set of holes works.
The final image here shows the caliper mounted on the bracket with an indication of where you might need to add shims. I didn't need any but that was because my brackets were custom made for the calipers & disc offsets. Looking at the Banks kit it looks as if he's supplied new bolts for holding the calipers in place - possibly those 4 blue bolts ? For mine I bought higher grade bolts and the threads were finer, I can't recall the pitch but they weren't your usual bog standard metric bolt.
If this doesn't get you sorted, post up photos showing where you're struggling and we'll take guesses !
Brian
