How do I add a linked card or account?

Tap the profile icon in the lower left corner of the app then tap "Linked Cards".  You will see a "Linked Accounts & Cards" screen, press the blue "Link Card" button at the top of the screen and add as many cards and accounts as you would like!  You can always remove a linked account by tapping the "Edit" button listed above your accounts and tap the red X to delete individual accounts.