It is recommended you contact a pool professional to winterize your pool properly.
Vertical Installation
Remove grate from upper SDX2 and install blow through plug and blow line until air comes from lower grate.
Install blow through plug in pump and blow line to achieve airlock to lower SDX2.
Horizontal Installation
Install blow through plug in pump and blow line to achieve airlock to SDX2.
This may not be the only means to winterize and may not be the best option in all environments. It is up to the service professional to provide adequate winterization.
Winterization anti-freeze is to be used as necessary or when required.