An extract from the instruction sheet:

The assembly, of the SDE Contact, in the tripped state (top row), must be carried out correctly.

The test is carried out from the ON position with (3). Below, there is a button.

The contact changes state when button (3) is pressed.

See link to the instruction sheet:

https://download.schneider-electric.com/files?p_File_Name=GHD1630301-05.pdf&p_Doc_Ref=GHD16303AA&p_enDocType=Instruction+sheet

Released for: Schneider Electric Belgium