sudo apt-get install samba
sudo nano /etc/samba/smb.conf

FILEADD:
[share]

comment = Ubuntu File Server Share
path = /path/to/the/folder  #for example /home/user_name/public
browsable = yes
guest ok = yes
read only = no
create mask = 0777
FILEEND;

sudo smbpasswd -a YOUR_USER

sudo service smbd restart
sudo service nmbd restart