First of all we need to install vsftpd from the lubuntu/ubuntu repository, open up your terminal (CTRL + ALT + T) and then type this command:
sudo apt-get install vsftpd
Once installed, vsftpd will automatically running on the background, you can go ahead try to connect using your current username and password that you use to login to lubuntu.
To connect to ftp server you will need ftp client, the client could be other machine (computer) that has the same network as the ftp server.
One of the best ftp client is filezilla, filezilla is available on both windows and linux, on lubuntu you can install filezilla using this command:
sudo apt-get install filezilla
To make ftp connection, you will need hostname/ip address of the ftp server, username and password, in this case username and password that you use to login to lubuntu.
If you want to create another user for ftp, then you need to create new user on your lubuntu, using adduser command, if you forget about this, read here.
You can also change configuration of vsftpd, by editing /etc/vsftpd.conf using your favorite text editor, for me i like using vim.
sudo vim /etc/vsftpd.conf
After editing that config file, you might want to stop and then start again the ftp server, here's command to start, stop and restart vsftpd server.
sudo service vsftpd stop
sudo service vsftpd start
sudo service vsftpd restart
That's all you need to know to create ftp server....cheers :)