I haven't "Add Relationships" button

I have created many tables like “Tickets”, “Drives” etc. Choosing “Tickets” table, then click on “Table Schema and Permissions” but i see 2 buttons: “Delete selected” and “Add Column” . What do I need to add a relationship?

Click the “Add Column” button and in the “Type” drop-down select “Data object relationship”:

See a screenshot here:

Mark