Server Side
Create operating system user accounts as per your requirements
useradd -g … -d … -m -s … -k … username
Create shares on the server, e.g.
/mnt/Disk2/shareA
/srv/samba/share3
Modify the /etc/samba/smb.conf according to your specifications
Add samba users with smbpasswd or pdbedit
smbpasswd -a username
pdbedit -a -u username
Modify permissions on the shares to match your requirements