Guild FTP confusion

Hello,

As a challenge/project I've decided to try and make a FTP server using Guild FTP.

I've made a group and users for it. I've set the one user to admin. The link for the site is: ftp://127.0.0.1 now I can get to it fine from my computer. But when my friends try and connect to it from their computers they can't. I'm sorry I can't give you more information not sure what more is relevant. If someone knows how to use this program or how to set up a server, I will give required information so you can help me.

Thank you
Max