I'm working with new generation KANBAN project.
Now, lots of completed issues are left on the right-most column ("Done") of the board.
I'd like to know how to eliminate them.
If possible, I want such completed issues to remain on Done column for a week and then go away.
Also in the backlog, there remains completed issues that have been never moved to the board.
Do I need to move them to the board to make them invisible in the backlog?