DND = Do Not Disturb
Turn this mode on when e.g. you want watch a game and don't want to be disturbed or perhaps you are waiting for your partner and don't want to be invited to play.
When in DND mode by default the 'Invite as Partner' feature is turned off and you will not see any adverts.
There are several ways to turn DND mode ON or OFF
1.) before one enters the club, there is a button to press on the 'green' page which says
[Do Not Disturb is On] or [Do Not Disturb is On]
Press the button to turn the feature ON (or OFF)
You can have the adverts ON or OFF and change Chat IN options.
Some examples show above.
2.) enter the club, press Settings -> Privacy: ->
Click: [Turn DND Mode ON] or [Turn DND Mode OFF]
Method 2.) also shows after having entered the club in DND mode.:
Online Server > You are in Do Not Disturb (DND) Mode, use Settings to turn DND off.