You have the large brake stay plate, with the huge circlip.
Then the caliper has a mounting bracket with 2 slide pins. If you have the correct stuff, there's nothing to explain.
Download a free manual, that may show you some more.
Many calipers will fit, you just may have to make a bracket. When I got my 86, it had a single forward slide pin and a rear pin mounted to a 3/4 x 3/4 piece of angle iron......
All our government does is distract us while they steal from us, misspend our tax $ and ruin our country