Q. How do I use the second y axis, secondYAxis function does not work

A. You can switch any series to the second y axis by clicking on the colored line to left of the series name in the legend below the graph. Alternately, use the "Display Styles" > "Series Specific overrides" to define an alias or regex + "Y-axis: 2" to move metrics to the right Axis

Q. How do I exit graph edit mode?

A. Hit the escape key or click the graph title and select edit again.

Q. How do I delete a dashboard?

A. Click that dashboard page's jag,then bottom will have an item "delete dashboard"