To enable a shape path for test entry:
Select the Text Along Path Tool.
Move your mouse cursor over a shape's outline until the outline becomes highlighted blue and the message "Click to Type on Path" is displayed.
Click to enable the path for text entry. A path is created, a text cursor is inserted on the path, and the Text Tool is auto-selected ready for text input.
NOTE: Once any particular path has been enabled, that path can be opened for edit at any time by simply double clicking on it with any of the Pointer Tool, Text Tool, Reshaping Tool or Rotation Tool selected (i.e. as for editing column text).