1.  You will need to download Microsoft Management Studio from Microsoft and have your database backup file in your pivate directory before restoring your database. You will need to find the name of your database as this is the only one you have access to.  You will Right Click on your database go to Tasks>Restore>Database...

2.  You will want to choose From Device (1) > click the ... (2)>Click Add (3) You then HAVE to use the directory c:\inetpub\vhosts\YOURDOMAIN.com\private and then put in your filename of your Database.  Click OK

3.  Click OK.

4.  Check the restore box and then go to Options.

5.  Check Overwrite existing database.  Update the directory if needed.  Click OK to restore, if you get an error that states your database is in use, you will need to turn off your domain in the Plesk Control Panel