On Windows, we recommend using WinSCP. Once it is installed, clicking the link on your "File manager" tab of your control panel will open up an FTP window, where you can navigate through the folders and directly edit files, simply by double-clicking on them. (We recommend installing it in this dual-pane mode, since it's easy to use.) You can also drag-and-drop files to and from the FTP window to upload or download them.
You can also open up the FTP in Windows Explorer without downloading a separate client. To do this, right-click on the FTP link on the File Manager tab and copy it, then paste it into Windows Explorer. But, this is a bit less convenient, as you'll need to copy any files elsewhere before editing them and copying them back.
On Linux or Mac, FIleZilla provides a similar GUI-based FTP option (it uses the same codebase as WinSCP).
If you wish, you can also connect to your FTP using encryption. To do this on Windows,
- Open up WinSCP, which should automatically pop up a "Login" screen".
- Right click and copy the FTP link on the "File manager" tab.
- Press Control-V to paste the link and populate the "Login" page.
- Under "Encryption", select "TSL/SSL Explicit Encryption".
- Click Login.