You can add an index to your PDF exports. To do so, you must first generate index terms, which you can do using either page labels or the Scroll Indexterm macro. Then, you can add the index terms you generated to your export as an index.
Generate index terms using page labels
Firstly, navigate to the page you want to insert a index term for, and add a label.
In the label, add your desired index term, and click Add. By default, a label is converted into a primary index term. To generate a secondary or tertiary index term, insert a forward slash character between the index terms.
fruits/apple/haralson will be converted into a primary index term 'Fruits', a secondary index term 'Apple', and a tertiary index term 'Haralson'.
Generate index terms using the Scroll Indexterm macro
Firstly, insert the Scroll Indexterm macro in front of a term you want to index.
Edit the macro, and enter the primary index term in the Primary field, and (if wanted) add a secondary and tertiary index terms in the Secondary and Tertiary fields.
Add an index to your export template
Once you have generated your index terms, you can add an index to your export template.
To do so, navigate to the template editor, and add the Index placeholder where you want to insert the index. If you also used page labels to generate index terms, navigate to the Settings tab and check the 'index terms' setting.