This dropdown menu you will see from the main issue window on the right side. 
Issue board list
From here you have a complete overview of all the issues boards.
New issue board 
Here you will open the window to make a new issue board.
Fill in the name, description and type and press add.
Statistics
Here you will open the statistics for that issue board.
- Overview
You will have an overview of all the open and closed issues on the board.
- Distribution
Here you have the accumulated status on open and closed issues.
The type distribution on the different issues.
- Plan reliability
Plan reliability measures your ability to close issues before it's due date.
Move history
This will show the issues that have been moved and where they have been moved to.
Import history
This will show the issues that have been imported and where they have been uploaded to.
Export history
This will show the export history inside issues.