After the initial sign up for Office 365, only the company administrator (of the first default account used to sign in) has rights to the SharePoint Team Site. Below are the steps to set up the SharePoint site.
1. Login to the Office 365 Portal and click the Admin drop-down menu on the top right toolbar and then click SharePoint.
2. In the SharePoint Admin Center, click site collections.
3. The right side of the screen will display the site collection URLs. Select the check box next to the main one (i.e. https://XXX.sharepoint.com), click Owners in the top toolbar, and then click Manage Administrators.
4. On the Manage Administrators page, set Primary Site Collection Administrator and Site Collection Administrator(s). There are no differences in the rights of the two, but the the Primary Site Collection Administrator is the only one that gets the email notifications about the site. So ensure the Primary Site Collection Administrator is the administrator that will handle the alerts on the site. Click OK when finished.