You need to restore a storage group from backup media or files.
Launch the Exchange System Manager.
Navigate to the server you will place the RSG on. Right-click, select New, and select RSG.
Set the name for the new RSG. If you are recovering from a storage group not already present on the server, you must set the name of the RSG to be the same as the name of the storage group you are recovering.
Provide the system path, as well as a path for the associated transaction logs. Make sure these locations have sufficient disk space and are not shared by other storage groups or transaction logs.
Right-click on the RSG and select Add a Database to Recover.
Select a database from those presented. If a database is already present in the RSG, you can only select other databases in the same storage group. Click OK.
Set the name for the database.
Provide paths and names for the database and streaming database files. These paths and names only need to match the original names if you are going to manually copy these files on top of the original database files after the recovery is complete.
Ensure that you have set the This database can be overwritten by a restore option on all databases to be restored.
You can now begin the restore process as outlined ...