How to make new copied file always 777 permission

add create mask = 0777 to the share definition, or to the global configuration, in /etc/samba/smb.conf for example:

[someidentifier]
    comment = open directory
    browseable = yes
    read only = no
    create mask = 0777
    directory mask = 0755
    path = /some/path/on/server

etc.

as for file ownership, there aren't any configuration settings for that, however, it seems who has ownership of the directory the file is created in will be the owner:group of the created file.

so, for the share in question, set the ownership:group to be what you want it to be, i.e.

chown john.users /some/path/on/server

See the Share Definition Access Controls section in the Samba manual. The create mask and related security options should allow you to set the file permissions as you've described.