To set up the MasterKey, just go to "New Password" section and create a new one, can be either your own password or generate one. Once the app ask you for "Add a Tag:" type in the Tag Textbox "masterkey" (Just that, not capital letters or spaces) and save it clicking on "Ok, save it" button. That's it! pretty simple.
Once you have created your MasterKey go to "My Passwords" section and click on "List of Passwords".
It will ask you for the MasterKey, just type the MasterKey that you have already created and press OK, it opens a list of all your Tags with your passwords, pick one and it will appear in the screen.
