Planning a bed with drawers under it based on this design:

https://store.chadhaus.com/products/loft-bed

I notice it has cleats on the side, but it also mentions "drawers with soft-closing/self-closing hardware for fluid action". Does this imply under-drawer slides or maybe slides that don't extend to the front of the drawers? I definitely don't want any visible hardware, but it would be nice to have smooth sliding.