Implementing dynamic Table of Contents?

In AEM Guides - 

Native PDF Engine:

1. Ditamap: You need to switch on the toggle from your Native PDF template :
   
    
   

    

2. For Bookmap, You need to set your structure to include toc in PDF publishing .

DITA-OT Engine :

There is no option in the standard DITA-OT engine for ditamap but you can publish dynamic TOC from your Bookmap

This Exl KB Article will answer your queries about Bookmap setup for publishing dynamic TOC: https://experienceleague.adobe.com/en/docs/experience-manager-guides/using/knowledge-base/kb-articles/publishing/native-pdf/how-to-include-bookmap-toc-in-pdf-publishing

-Pulkit