One of the most common issues I find people have initially with SharePoint Online via Office 365 is adding new users. Most think that simply creating a new users and assigning them a SharePoint license automatically gives them access to SharePoint Site Collections. It doesn’t. Why? Because what security rights do you provide that user in SharePoint? Are they going to be an administrator or are they going to be a ‘normal’ user? That’s why they need to be added manually to each Site Collection.
Basically, all you need to do is login to the SharePoint Site Collection as a SharePoint Administrator and give the new user permissions. How about rather than telling you I show you via this video I’ve just uploaded to my YouTube channel.
I hope that makes it a bit easier to get started with SharePoint in Office 365.