Open the top level stack, and get ready for you first data entry...
Click the "Create Peer" button to create a new live data card in your top stack. Put the appropriate name in the "Self Name" field. (The cursor will automatically be in in the "Self Name" field when you first create the new peer card.)
Step 9:
Put some information in the large "Data" field, if you wish.
Create as many additional Peer Cards on this level as you want.