The barn door hardware is,sold at. Most hardware stores with directions. You'll need to order or make doors several inches taller than existing. Doors as they are usually mounted just above the door frame. Make sure you have the room on either side of door to slide back to.
Barn door hardware is surprisingly expensive for what it is. I would shop around quite a bit.
We added a sliding barn door using closet hardware. This might work for you too. https://michellejdesigns.com/our-kitchen-remodel-part-3/ Then we made some mini barn doors on this little piece of furniture. So maybe this might work on a larger scale for you. https://michellejdesigns.com/cat-litter-box-furniture/