If you set Position in "Customize the table of contents" to "Specify class name," the table of contents is displayed as the first child of the element with that class name. If more than one element has the same class name, only the first one is used. It cannot be placed in the middle of the element, or immediately after a specific child.
Prerequisite: Add the "Table of Contents" app block to the theme, or add an app embed on a vintage theme.
(1) Check the class name at the position you want
Check the class name of the element where you want the table of contents. Do not enter the leading dot (.).
For example, if the article body element is article--content or rte, enter that string.
(2) Change the position
Open "Customize the table of contents" from the app menu, then select "Specify class name" for Position.
(3) Enter the class name and save
Enter the class name in the field, then select "Save."