Add at least 1 access node for SharePoint Online. For high availability (which is recommended for the first full backup), use 2 or more access nodes.
Before You Begin
You need the following information:
User name and password
From the navigation pane, go to Manage > Servers.
The Servers page appears.
In the upper-right area of the page, click Add access node.
The Add gateway dialog box appears.
From the Select packages list, select OFFICE365, and then click OK.