Select "More" from the bottom menu bar:
In the search bar type in the name of the person you want to connect with:
When the person that you want to connect with appears select the connect icon:
Shuffle will confirm that you want to connect with this User:
You can check the status of your connection under "Outgoing"
Please note that you will not be connected until the other Shuffle User has accepted your request.
Once connected, you will see the other Shuffle User in your "Contacts". Make sure to request cards or start Chatter with the User that has an "Shuffle Icon" next to their name:
See this in action: