Shelf is solid wood, looks nice enough, if you like the style.

I'd hang it with some angle brackets under the shelves. These brass ones come in a 4 pack for $3: https://www.lowes.com/pd/ReliaBilt-RB-3-4-IN-SB-CORNER-BRACE-4-CT/5001634841

Screw one side into the underside of a shelf with the provided brass screw, other side into the wall with longer screw. It'll hold 100+ pounds if you get 2 of them in a stud.

You could use picture-hanging hardware as others are suggesting, but eventually somebody is gonna put something heavy on the shelf. Also, someone could grab it for support.

Nobody ever regretted making a shelf stronger...