If you need to manually restore an SQL Database in Management Studio you can follow the instructions below for the version of SQL Server running on your server.
1. Log onto SQL Server Management Studio.
2. Navigate to the database you wish to restore.
3. Right Click > Tasks > Restore > Database.
4. Once on the General tab set the source to Device > Select Backup Device > Add > Navigate to the .bak file you're restoring to.
5. Ensure the Destination Database is the correct one.
6. Select the Options tab.
7. Check "Overwrite the existing database (WITH REPLACE)" and "Close existing connections to destination database".
8. Uncheck "Take tail-log backup before restore".
9. Click OK.