I removed the shelf and drawer from my refrigerator to work on it. Using a small hammer, drive the slides forward to remove. The slide is universal, one part fits both sides. Insert the replacement slides into the 3 slots, use the hammer to drive the slides backward until seated. This can be a little challenging, but it is do-able. I had one that was easy, one that was a little more challenging. Once the new slides are installed, replace your drawer and put the shelf assembly back into the refrigerator and you finished. The new parts are working great for me.
NOTE: A small ball-peen hammer is very useful. Also note that there are small, round, plastic buttons (raised from the surface) of the slide that can make it challenging to get the inserts of the rail to slide. I have read some folks ground those down to make the replacement easier. These serve a purpose - to keep an outward pressure applied once the slide is installed, so it does not simply slide out each time the drawer is moved forward.