A quick and easy way to upload and download files with Mozilla Firefox is to use FireFTP. There are plenty of ftp client to use, I just find this one simple to use. FireFTP is a small add-on to the Firefox browser. Go to Tools, Add-ons. On the top menu, choose Get Add-ons. In the search field, type FireFTP.
Follow the instructions to download. If you have trouble finding it, click on the link below.