Create Sharepoint group and assign permission, Sharepoint online

Using c# i would like to create a sharepoint group and assign a permission to that group. According to this: http://msdn.microsoft.com/en-us/library/fp179912.aspx i am able to create roles, add a user to a sharepoint group etc., but i doesnt explain how to create a sharepoint group. I am using sharepoint online, o365. 

Can anybody help me?