Silver,
A few things. I downloaded a Bimba cylinder from
www.3dcontentcentral.com The rod is free to translate. Make certain this is your case in the assembly.
There are three forms of animation/motion.
If you want path/trajectory/force, you need to Add In SolidWorks Motion,
I highly recommend you review two SolidWorks Tutorials 'SolidWorks Animation' and 'SolidWorks Motion' under Help>SolidWorksTutorials.
You can perform basic motion under "gravity" from the motion tab. The Linear motor is available- but the cylinder has no straight edge, so you will need ot insert an Axis, under Insert, References, Axis.
For motion analysis (kinematics) you need to add in SolidWorks Motion and then select Motion Analysis from the Motion Manager. Select Linear Motor. Select the cylindrical face of the rod and the direction. Click inside the Component to Move Relative to box and click the housing of the cylinder.
Marie