You want to start by doing some tutorials.
Are you interested in Structural Dynamic Anlaysis (motion + stress/displacements/strain) or just Multibody Dynamics (just the motion)? For the first you want to learn SolidWorks Simulation, for the 2nd you want to learn SolidWorks Motion.
You can find SolidWorks Tutorials from within the software itself!
You have Tutorials on most almost everything you can do with SolidWorks!
If you go to SolidWorks Simulation Tutorials you will find the Motion Tutorials
If you require Dynamic Structural Analysis then click on SolidWorks Simulation Premium Tutorial and at the botton you will find Linear Dynamics. I'd recommend doing every Static Analysis tutorial first, so you can get familiriazed with the subject first.
YouTube is also great for finding tutorials on how to use SolidWorks.
If you find specific doubts, you can always come back to the forum and I'm sure someone will be able to help you on the specifics!
I have a mechanism controlled by a motor. I want to perform simulation of rigid body dynamics and obtain the torque, angular velocity and rotational angle of various joints while the mechanism is in motion.
Go to Tools>Addins and make sure advanced motio is selected.
Then make sure you select this as your active environment rather than animation or motion.