When connecting to the RedShelf FTP, it is important to remember that the FTP tool (file transfer protocol) pre-dates the world wide web (what we typically think of as the internet). So you are unable to use a web browser (chrome/firefox/internet explorer/etc) to access it.
For some additional information check here.
The recommended tools to use are
Both are free to download and use for the public. If you can make a donation to the developers, please do so (WinSCP and Cyberduck).
There are other tools available that are paid or subscription based that include a multitude of features, improved ease of use, security upgrades, and have multi-user or platform configurations. OR include a ton of spamware that installs and runs in the background on your computer, degrading your machine, and your overall computer usage. If you can afford to use a purchased FTP tool, it it recommended you go that route. Otherwise, RedShelf recommends, and uses both of the tools listed above for all of its employees.
Go HERE for the WinSCP documentation
Go HERE for the Cyberduck documentation
If you are on a Windows computer, the FileExplorer window already acts as an FTP client, so an additional tool might not be needed. It's not the prettiest interface, but it does function perfectly.
Finally, there is no documentation on this site if you use the cmd or ssh windows to connect to the RedShelf FTP. This is under the assumption that if you are able to make that connection, then anything here would just make it more confusing.