[MM3-users] need help to migrate from Mailman2 to Mailman3 (french if possible)

Hello everybody, I'm trying to migrate my mailing lists on Debian 11 server from Mailman2 to Mailman3, and I'm having difficulties ! Mailman3 is already functional, but I could not configurate Postfix for this. Is there anyone speaking french that could help me ? Thanks in advance.