First, an obvious but vital safety warning: Unplug the fan.
1. Remove two rubber plugs on the upper part of the rear panel to expose two Phillips head screws, and remove them.
2. Remove fan's base to expose the fan's drive shaft, and remove the C-clip, two washers, and the oscillation armature
3. Remove two Phillips head screws to the rear (in the two plastic holes)
4. Push inward on both sides half way down the rear panel and remove the rear cover
If you wish to tear it down further, it is a fairly straight forward combination of screws.