Top and bottom rack were rusted thru

Bottom rack - slide the old one out, slide the new one in. The rack came came with the wheels, so I didn't use the replacement ones.
Top rack - remove the rail end caps - they will likely break so order new ones. Slide the rack out. Remove the rotating spray arm and then remove all the brackets. I was able to re-use the old brackets and didn't need the replacements. Install the old brackets on the new rack, install the spray arm, and slide the new rack back into the rails. The new top rack also came with wheels installed, so I didn't use the replacement ones. Once the rack is back in the rails, install new rail end caps. Put them in sideways and facing into the washer. Straighten the caps and turn them into place. Be careful with the rail caps - they break easy and are expensive. Make sure they hold the top rack in place, and that's it.