Like carve out a place between Russia, Belarus and Ukraine in the former Pale of Settlement. Establish a bunch of Yiddish language schools there. Have it become a center of Jewish culture. Sure, there are already Ukrainians, Russians and Belorussians there but there were already people in the far east too.
I'm answering what they meant. Napoleon is the example of integrating Jews. No one here is arguing thats best or that can work in liberal societies without all the drawbacks