The clear piece comes with the unions.. The way I have everything in the pic, is exactly how it goes when installing on the car.

Step one

Slip the nut over nylon line, then put the clear sleeve over the end of the nylon line, assemble union to nut at nylon line.. NotIce that the nylon end has an inner stem on the union

Step two

Slip the nut over the steel line on car, then the metal sleeve, then attach union to steel line on car