Hi Emily
Open Memento Application
on " my libraries" screen select menu and then settings
About half way down the settings list you should see Backup
Select that and it will create a .db file of all of your memento databases and show you the path where it will be saved.
As mentioned by someone earlier if you have memento pro you will also see an option to save all audio, images and other files.
Click ok when you are ready
Now you need to connect your phone to a computer and copy the memento_backup.db file onto the computer.
Now attach your new phone and copy the same file from your pc to your new phone into the same directory structure.
Now start memento on your new phone and go to settings and Restore.
You should see the copied file shown with date and time.
Select that and your database will be restored to Memento on your new phone.
Word of warning.... this worked fine for my database with one exception. I had a lot of contact fields in my original database entries which link directly to contacts on the phone. On the transferred database these were all out of sync and mixed up. Havent quite got to the bottom of it yet but its either because I had added a new contact to the new phone before transferring the database or because some contacts in the original database were from google, or outlook or linked in or whatever. Not sure how memento deals with this kind of thing but either way I had to reset the contacts manually. Only had 26 entries in database but some of them with 5 or 6 contacts it suddenly makes for a lot of manual re doing to get them showing the right entry.
Ian