There is a great webinar recording for those interested in Jewish Genealogy in Poland done by "Your Roots in Poland"
Its titled Mishpokhe. Jewish Polish Genealogy, Part 1: Pre-WW II Jewish Family History
It requires free registration but I definitively suggest you to view it till the very end, including the Q&A
Very soon they will advertise Part II. I will try to keep you updated so you can enjoy it live.