8 3/4 rear disc conversion question

How do they connect? Exactly the same way the flex hoses connect to the hard lines on the front brakes. The flared steel line just screws into the fitting on the end of the pre-made rubber hose. There is no in-between piece. I bought the SSBC kit and it came with all the lines and hoses. The little bracket shown in your picture is not included, instead they use big zip-ties to hold the lines to the axle.