There are two arms on the hinge end that fit into holes in the cargo area floor. Then there are two spring loaded hoops that are fed into strikers along the window sill. You might have to play with the release button to get the hoops to align with the strikers. The hoops aren’t well retained. If the clips and hoops come off, you might lose the torsional springs that keep the hoops in contact with the release button.

Sixto
98 E320s sedan and wagon
02 C320 wagon