It is assumed that you have created a Gmail backup to another cloud app as shown:
Google Drive

Here are short instructions on how to create restore of cloud app’s email backup to Gmail:

  1. Start synchronization wizard to sync two cloud accounts
  2. Click on cloud app where email was backed up, i.e. Google Drive, so click Google Drive icon

    Google Drive
  3. Select one of already configured Google Drive account or click on “Add Google Drive” to add new Google Drive account

    Google Drive
  4. If you click on “Add Google Drive” you will be forwarded to authorize cloudHQ to access account

    Add Google Drive
  5. Select where backup is in Google Drive and click “Next”

    Google Drive
  6. Select Google Drive folder where backup to be restored is located

    Google Drive Folder
  7. Click on Gmail icon. The sync will automatically switch to one-way sync to restore email backup

    Gmail icon
  8. Select one of already configured Gmail account where backup is to be restored into

    Gmail account
  9. If you click on “Add Gmail” you will be forwarded to authorize cloudHQ to access account

    Add Gmail
  10. Choose options and synchronization starts automatically

    Start sync
  11. Synchronization status will display after initial synchronization
  12. Synchronization will start – Here is How to Monitor Status of Sync
  13. An email will confirm success of initial synchronization