Surprising: The parts were mostly pre-assembled!
BUT: Without technical knowledge, it is still difficult to assemble because the included instructions must be inaccurate or does not show the delivered model. Just the details, such as the fastening points of the braces can not be seen. Here it must be "tried".
The pre-drilling some holes is recommended in order to prevent the bursting of the timber.
One criticism (so 1 star deduction): The inner light level is only about 90cm, unfortunately that is triple split 1-meter wooden apex (=> 33 cm) can not be interpreted in a row! I have therefore further asked the shelf accordingly away from the wall. Then it fits again!