Did you just blank out your contacts there for privacy? Thought at first you had none . . .

On version I have, there's a little button next to each contact with three horizontal lines instead of "add" like yours, but probably works the same. A little bit unusual for a configuration dialog, but good enough. One just clicks that button, sees a list of possible shortcuts for the contact to add to desktop and then selects one. Then close the config and the squircles with the contact's picture (if you have one) or initials will have appeared on your desktop, probably at end of list. A little lime green overlay indicates whether the squircle launches a voice call, text or contact card. Move that around to suit your needs and there you go: one click to call.

Works fine for me.