This article will show you how to convert a normal heading to a checklist item or a workflow step. This can only be done in the desktop editor.
Verify that the article type is Checklist or Workflow
You can only add checklist items to articles of type Checklist or Workflow and you can only add steps to articles of type Workflow articles. In the Article Inspector verify that the type is set to Checklist or Workflow.
Locate the heading you would like to convert
One way to tell the type of a content block by looking at the icon in the outline. You can convert content blocks with the "H" icon which are headings. In the screenshot below, (1) is a checklist item and (2) is a heading.
Right-click and change type
Right-click on the heading and select an option from the Change Type menu option in the contextual menu that appears. In the screenshot below a right-click was performed on the Perform another task heading.
The heading type will change to the type you selected. In the following example the heading has been changed to a Step content block type in a Workflow article.