Steps involved:
- Create the Recovery Storage Group
- Restore the Storage Group that has the database of the mailbox to be restored to the Recovery Storage Group
- Mount the database in that Recovery Storage Group
- Create an empty mailbox (AD User + Mailbox)
- Restore the mailbox to the new mailbox
Restore-Mailbox -RSGMailbox 'Doe, John' -RSGDatabase 'Recovery Storage Group\Mailbox Database 01' -id 'new mailbox' -TargetFolder 'myFolder'