Off the main Atlas page after logging in:
Step 1:
Click the Employees Tab on the left, then under "My Human Resources" click "Update Your Information" and lastly "Update My Personal Information"
Step 2:
Click on "Personal Information":
Step 3: Modifying Entries
Click the appropriate icon, depending on whether you wish to:
Edit 
Add 
Delete
Steps 5 & 6:
Whether Adding or Updating an address or phone number. The screens will look similar, and you will fill in the information as appropriate and click "Add" or "Update" as indicated. See below for reference:
Note: if you wish to remove a phone number or address you would click the delete icon
You will then be prompted to confirm as shown below:
