Miele WTW 870 WPM Operating Instructions Manual page 27

 Remove the foil from the detergent
cartridge.
 Open the access panel for TwinDos.
Before the first use
 Push the UltraPhase 1 detergent
cartridge into compartment 1 until it
locks into position.
The following message appears in the
display:

Now enter the settings for UltraPhase 2.
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