The only thing you need is :
Put the logon.bat scipt in the map:
/var/lib/samba/sysvol/domainname/scripts
Where domainname is the name of your domain.
In the webadmin gui "Domain" select a drive letter for your home map.
Put the windows clients in the domain ( domain PDC must be also DNS server, the windows clients must be poited to the PDC DNS ).
There is no other setting needed ( no GPO nothing else ).
Best regards,
Ian