this cannot be just a simple heres a video enjoy!
there are 2 parts to this, trigger by switch, a simple google search for a youtube tutorial will bring up plenty of ways to interact objects.
the aniimation of the fan is different based on your mesh.
Now easiest way would be a 2 part mesh 1 for the celing pole and another for the fan blades. it could be as simple as setting a looping rotation blueprint on the blades.
do you have the fan mesh already?