Attached the first servo motor using the screws included in its package. Then on the output shaft of the servo to secure a round horn a bolt.
And on top of it, place the upper part and secure it using two screws.
Here again first goes servo, then the round horn onto the next part, and then they are secured to each other using the bolt on the output shaft.
Use a rubber band to give some help to the servo because this servo carries the whole weight of the rest of the arm as well as the payload.
Continue to assemble the rest of the robot arm. As for the gripper mechanism utilize some 4 millimeters bolts and nuts to assembly it.
Finally attach the gripper mechanism onto the last servo and the Arduino robot arm was completed.