To add a contact log onto your email account via a web browser and click on the Contacts button. This will open a list of your contacts.
Click on the "New" button at the top of the list of contacts and select "Add Contact".
This will bring up a contact box. Enter the details in the name fields.
When you want to enter the email address, place it in the box marked "Home" and tick the box "primary".
If it is not their "Home" address, use the smaller box marked "Home". This will give you a drop down box that you can select from.
Complete the form with as much or as little detail as you wish and click "save" at the top.
To add a contact to a group, you first have to have the contact in your list of contacts. Once it is there and you have a "Group" set up you simply drag and drop the contacts that you want from the contacts list into the "Group" or you can select the contact and use the "Add to Group" button on the menu bar above the "Contact Card"
To remove a contact from a Group you need to tick the box to the left of the contact then move your mouse to the right hand side and it will reveal a choice of options including one to delete the contact from the "Group".