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.
Do what Napoleon did and stop legally disenfranchising them. Jews in Europe often still had dubious legal protections if any, even just ensuring they have citizenship and protection would be integration on a radical scale
Any liberal state will take away their rights as soon as there are capitalist crisis and shift the blame towards "the other" and that means if election leads to right wing leaders of state sooner or later rights might be taken away (as we could see quite often even after 1945 in Europe).
Since liberal parliamentary states don't seem to be able to stop antisemitism and the reaction.
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