A method to pick up and transport items, the method using a robot configured to pick up and transport items; wherein the robot comprises a pick up unit, wherein the pick up unit comprises a pick up device configured to pick up and release items, wherein the robot is configured to move the pick up device along a first direction, rotate the pick up device around a first axis, and extend and retract the pick up device along a second direction different from the first direction; wherein the robot further comprises a shelf unit configured to temporarily store items, wherein the shelf unit comprises a rotatable portion and a support structure, wherein the rotatable portion is rotatable with respect to the support structure; wherein the rotatable portion of the shelf unit is rotatable around a shelf unit rotation axis that is parallel to the first axis, wherein the connection between the first axis and the shelf unit rotation axis defines a connection line; wherein the rotatable portion comprises a plurality of case boards for supporting the items; the method comprising the robot travelling to a first shelf; the robot picking up a first item by means of the pick up unit; the robot transferring the first item to the shelf unit after the robot picking up the first item; the robot picking up a second item by means of the pick up unit; and the robot transferring the second item to the shelf unit after the robot picking up the second item; wherein in the step of the robot transferring the first item to the shelf unit, the first item is placed on a case board, and in the step of the robot transferring the second item to the shelf unit, the second item is placed on said case board, while the first item is located on said shelf board, characterized by the method comprising in the step of the robot transferring the first item to the shelf unit, the pick up device assumes a first pick up device angle configuration with respect to the connection line and the rotatable portion assumes a first shelf angle configuration with respect to the connection line, and in the step of the robot transferring the second item to the shelf unit, the pick up device assumes a second pick up device angle configuration with respect to the connection line and the rotatable portion assumes a second shelf angle configuration with respect to the connection line, wherein the second pick up device angle configuration differs from the first pick up device angle configuration by a pick up device difference angle, the second shelf angle configuration differs from the first shelf angle configuration by a shelf difference angle, and wherein the pick up device difference angle equals the shelf difference angle. wherein the robot comprises a pick up unit, wherein the pick up unit comprises a pick up device configured to pick up and release items, wherein the robot is configured to move the pick up device along a first direction, rotate the pick up device around a first axis, and extend and retract the pick up device along a second direction different from the first direction; wherein the robot further comprises a shelf unit configured to temporarily store items, wherein the shelf unit comprises a rotatable portion and a support structure, wherein the rotatable portion is rotatable with respect to the support structure; wherein the rotatable portion of the shelf unit is rotatable around a shelf unit rotation axis that is parallel to the first axis, wherein the connection between the first axis and the shelf unit rotation axis defines a connection line; wherein the rotatable portion comprises a plurality of case boards for supporting the items; the method comprising the robot travelling to a first shelf; the robot picking up a first item by means of the pick up unit; the robot transferring the first item to the shelf unit after the robot picking up the first item; the robot picking up a second item by means of the pick up unit; and the robot transferring the second item to the shelf unit after the robot picking up the second item; wherein in the step of the robot transferring the first item to the shelf unit, the first item is placed on a case board, and in the step of the robot transferring the second item to the shelf unit, the second item is placed on said case board, while the first item is located on said shelf board, characterized by the method comprising in the step of the robot transferring the first item to the shelf unit, the pick up device assumes a first pick up device angle configuration with respect to the connection line and the rotatable portion assumes a first shelf angle configuration with respect to the connection line, and in the step of the robot transferring the second item to the shelf unit, the pick up device assumes a second pick up device angle configuration with respect to the connection line and the rotatable portion assumes a second shelf angle configuration with respect to the connection line, wherein the second pick up device angle configuration differs from the first pick up device angle configuration by a pick up device difference angle, the second shelf angle configuration differs from the first shelf angle configuration by a shelf difference angle, and wherein the pick up device difference angle equals the shelf difference angle.