Understanding a switched-mode power supply datasheet
What you have here is not a switched-mode power supply, but only a part of one. This is a transformer intended to be used as part of a flyback converter. If you apply 50/60 Hz AC to the primary winding, you won't damage it, but what you get out will be AC again at an unpredictable voltage. This device is designed to work with high-frequency AC from a switching circuit, and its output is again high-frequency AC that needs to be rectified and regulated. The coil marked "aux" is a feedback coil, part of the control mechanism of this type of converter.

I'm not familiar enough with flyback converters to properly explain how this is meant to be used, though, so if anyone wants to do that go right ahead.