In this video and tutorial is explained how to animate objects with Blender. The author uses Blender 2.9 for the tutorial but the techniques apply to Blender 2.8 as well.
First two simple objects, based on a cylinder are created, to buid a screw-like object. Important is the placement of the pivot point, especially for the first object, which is scaled during the animation.
After the two objects are added and placed to theier locations, the thimeline window is used to add the keyframes for the anmations.
A keyframe stores the values for the transform of an object (scale, location and rotation) at a certain point of time. By default the values are interpolated between the keyframes.
The first object is scaled and rotated, the second one is moved and rotated:
The keyframes for the first frame and last frame are copied (Ctrl-C and Ctrl-V for selected keyframes) so that the result is a cyclic animation.