Open Traffic Travis 4, then go to Service > Open DB Folder.
You can also find the database folder without opening TT. To do this, you need to search for the Traffic Travis file folder. Please run a search by entering "Affilorama" in your file search tab.
If that doesn't work, try typing %appdata% into your search tab. The folder "Roaming" should appear. The Affilorama folder will be located within Roaming.
Once you have located the Affilorama folder, you can find the database folder by going to Affilorama > TrafficTravis4 > databases > projects.
Copy that folder to another folder to create the backup.