Working with backup sets : Cloud (Salesforce.com) backup sets (Windows) : Creating a Salesforce.com backup set : Specifying the server
 
Specifying the server
1. Select the Cloud Server to backup.
The Enter Network Credentials dialog box appears.
F1 Help: "Specify Credentials (Windows DS-Client)"
2. Type the credentials to the (Salesforce.com) Cloud Server, and then click OK.
3. Type the Salesforce.com username and password.
4. Select the target database for backup (Production or Sandbox).
5. Enter the security token that was sent to you by email from Salesforce.com. You can request for a security token from the Salesforce.com website (Click Setup > My personal information > reset my security token).
6. Click OK.