To create a BACPAC backup, do the following steps:

1. Open Management Studio and connect to the database server.
2. Right click on the database you wish to backup and select Tasks > Export Data-tier Application...
   
   
3. In the dialog that appears click "Next >"
   
   
4. In the Export Settings window select "Save to local disk" and click "Browse..." to select the destination of your BACPAC backup file.
   
5. Select your destination and give your file a name, make sure you manually type in the extension ".bacpac"
   Click "Save"
   
6. Confirm your BACPAC file destination and click "Next >"
   
7. Review the summary and click "Finish"
   
8. Your BACPAC backup is complete!