3 Kallax Bookshelves from IKEA

Some kind of a decorative edged top for the kallax shelves

Some kind of a MDF back for the Kallax bookshelves to add structural support for the frame

If possible, doors for the kallax bookshelves

Install on the side, and place the existing bookshelves above the kallax bookshelves

Add decorative columns from Outwater on the shelf vertical sides

Add crown moulding on top