Hosting FTP Server in internal network?

Hi! I'm trying to setup WinSCP in my PC that is connected within a LAN in my University. I'm wondering what is my actual IP that my friends from outside the network must use to get connected. How can this be done?

Thank you.

It seems like tou consider WinSCP for be a FTP server. WinSCP has nothing to do with FTP and it is not a server, only SCP/SFTP client.