Action is a script that is launched when pressing the certain toolbar icon. To create a new Action, go to Scripts, click 
icon from the Toolbar and choose Action option.
Then follow the steps below:
- Define the Name for the Action
- Select whether the Action is executed for an entry or for the whole Library
- Add Script — lines of code
- Switch to Arguments tab if you need to define the values the user enters to be used inside the script
- Using the toolbar above the Script field, you can Run the Trigger, set the Permissions for it or get Help
Before you start, visit wiki to get to know more about Memento Database syntax and the features of Actions.