Taddhita pratyayas are one of the most important pratyayas in Sanskrit. Neelesh is conducting a six months course that has started today.
पाणिनीयव्याकरणस्य तद्धितप्रकरणस्य पठनार्थं निर्मितः जालपुटः – https://sites.google.com/view/setu-taddhita । The classes are held every Saturday and Sunday from 10:30 AM to 12:00 noon IST. Anybody who wants to learn तद्धितप्रकरणम् using अष्टाध्यायी is welcome to attend the classes.
You may join this group to get notified – https://groups.google.com/forum/#!forum/setu-taddhita
Even without joining the group, you can access the links to directly join the sessions in Hangout or anonymously in YouTube – https://sites.google.com/view/setu-taddhita
Here is the video of the first introductory class.
Here is the playlist which includes this series of sessions on Taddhita