If you have enabled the "LocalCopy" option for your backup, the restore process is a little different than restoring from the backup server.
1. Click the "Decrypt Local Copy" button in the bottom tool bar:
2. Select the backup set you wish to decrypt
3. Click "Next>"
4. Select the files you wish to restore. Click the main checkbox to select all files
5. Set the restore destination. This can either be the "Original Location" or you can set an alternate location
6. Click "Start Decrypt" to begin the decryption. Depending on the number and size of the files being decrypted/restored, the restore time will vary.