To create a group, simply click on the Group icon in the left sidebar menu. A new box will slide out to the right. Click the "+" button and you can then create a group.
You can then select your Group from the list below to start adding your Contacts. To add your Contacts, you can either upload a .xlxs, .xls or .csv file (spread sheet requirements below) into the Group, or you can add them individually from your Contacts list using batch actions.
Hitting Add to Group will allow you to select the group to add Contacts to
Next up select the Contacts to add by using the check mark and hit the Green Plus button to add them into the group!
To add from a spreadsheet, create the spreadsheet using the formatting above and save it to your desktop. Then, click the button to Upload Contacts. Your Contacts will then be added in the Group as well as in the Contact list!