Here are the steps to backup your SQL database in SQL Server 2012.
Close SellerDeck on all machines
Open 'Microsoft SQL Server Management Studio'
Right click on the database and go to 'Tasks | Back Up'
This will open the 'Back Up' window. In the General tab, choose 'Backup Type' as Full.
For 'Destination' choose Disk.
If you see anything in the list, highlight it and click ‘Remove’
Then click ‘Add’ to choose the backup location, and choose a unique name
Once you have chosen the backup destination, highlight it and then click 'Options' in the main backup window.
Choose ‘Overwrite all existing backup sets’ and press OK
You will then get a message saying the backup was successful
Do the same for the shipping database
You will now have two .bak files in the destination you specified