There are two major joints that allow the solar arrays to rotate, the Alpha and Beta gimbals.
Note this is a discussion of the main 4 arrays at the opposing ends of the main truss. The Russian segment has its own solar arrays, and there used to be a plan for more. There have been a series of proposed Solar Power modules for the Russian segment that keep getting cancelled for budgetary reasons. The current plan calls for the Nakua modules to dock to where Pirs is (earth facing port of Zvezda) and then have the UM (Universal Module) with 6 docking ports, dock to the bottom, and then have the Solar Power module dock to the UM.
These two joints allow the panels to rotate to track the sun as needed. The alpha gimbal allows them to rotate as if in a circle, centered on the truss itself. I.e. Imagine the panels windmilling with the center on the truss.
The Beta gimbals allow the panels to tilt around to accommodate inclination changes in the sun.
Also on the truss, are the thermal radiators to dump waste heat that rotate to AVOID direct sun exposure so they can better dump heat into space.