How can I find the FTP login if nobody knows what it is?

[Conor_Tomkins]

You can't.

Contact your server host and request them to reset it.

[theMageComp]

Hello @bfranco ,

Login into your Cpanel (hosting) > Look for FTP accounts > You will be able to see the list of FTP accounts created in your account. If not create one from there, you will need to enter username, password and path you want to access. 

[magesolutions]

Not sure if you are using shared hosting or vps/server. If you use hosting then you are easy to figure out the ftp login in cpanel (or any server control panel). If you use vps/server, you need to install a ftp server like filezilla server or sftp