These topics review 'basic-kinematics' theory. They do not explain how to use MechDesigner.
These topics help you identify Rigid-Bodies, Joints and Motion elements in a kinematic-chain, so that you can use MechDesigner more effectively.
To learn how to add and edit the elements, you should look at the Getting Started Tutorials and the MechDesigner Reference Help.
Kinematics and Kinematic-Chains