Assign New Part Data to a Blank Stencil or Connector Line

Select or add the desired stencil or connector line on the Drawing Tool canvas.
Locate the part data and labeling fields in the Element Info controls in the toolbar OR right-hand side panel OR the interface surfaced when you double-click a stencil.

Note that connector lines are not provided with an on-canvas part data interface, and must be modified in the right-hand side panel or toolbar.
Click the + symbol to the left of the part name field to create new part data and assign it to the selected element.

OR

Select Add Number from the context menu presented when the element is right-clicked.
A new part will be created and your element will be assigned its data.
Add a part name for your new part in the Element Info or Parts Panel fields provided.

Further updates to assigned part data made in the Element Info or Parts panel interfaces will be reflected in all on-canvas elements with that part data assigned.

Assign Existing Part Data to a Blank Figure Element

Select or add the desired stencil or connector line on the Drawing Tool canvas.
Locate the part data and labeling fields in the Element Info controls in the toolbar OR right-hand side panel OR the interface surfaced when you double-click a stencil.

Note that connector lines are not provided with an on-canvas part data interface, and must be modified in the right-hand side panel or toolbar.
Click the # symbol to the left of the part name field to select existing part data to assign to the selected element.
Select the desired part from the list provided.
The selected part data will be assigned to and displayed on your figure element.

Further updates to assigned part data made in the Element Info or Parts panel interfaces will be reflected in all on-canvas elements with that part data assigned.

Select or add the desired stencil or connector line on the Drawing Tool canvas.
Locate the part data and labeling fields in the Element Info controls in the toolbar OR right-hand side panel OR the interface surfaced when you double-click a stencil.

Note that connector lines are not provided with an on-canvas part data interface, and must be modified in the right-hand side panel or toolbar.
Click the part number field to assign a new part number.
Select the desired part from the list provided.
Your on-canvas element will be assigned the data for the selected part.

Select or add the desired stencil or connector line on the Drawing Tool canvas.
Locate the part data and labeling fields in the Element Info controls in the toolbar OR right-hand side panel OR the interface surfaced when you double-click a stencil.

Note that connector lines are not provided with an on-canvas part data interface, and must be modified in the right-hand side panel or toolbar.
Click the x next to the part number.
The part number will no longer be associated with or appear on your on-canvas element. The element label will still include the text of the part name, which you can delete if you wish.

Note that following these steps will leave both the figure element and the part data intact, but unassociated. See additional steps on how to delete a figure element or delete a part.