The part on the left, with the tall wall and perpendicular rectangular compartment is one piece, while the low shelf and open bookcase part on the right is another. You can separate them or squeeze them together however you want! Plus, it comes with everything you need for assembly, including a screwdriver.
Promising review: “This shelf is so well made. The material is very solid and durable and really good quality. It was easy to assemble and aligned perfectly. So many of these I buy are cheaply made and don’t align, so this one is top notch! Also it was much larger than I expected, but the double-shelf design allowed me to adjust it so it would fit. I highly recommend this product to anyone looking for a great shelf for their desk that’s beautiful, easy to assemble, affordable, and sturdy!” —Jennie Sydney
Get it from Amazon for $26.99 (available in four colors).