To become a True Account, you must use a private domain business email address. ISP email addresses (e.g.: AOL.com) or free email addresses (gmail.com) are not valid. A private domain email addresses is like xxx@Microsoft.com, but not xxx@live.com.
To download multiple files, you cannot use a web browser. If you don't mind install software, then DriveHQ FileManager is the best client software. It has a lot of best features; you can easily drag and drop many files / folders reliably.
You can also use any FTP client software, incl. Windows Explorer. For more info about FTP, please visit:
http://www.drivehq.com/ftp/ click on FAQ and Expand All.
Using Windows Explorer (not Internet Explorer), you just need to enter this address:
ftp://USERNAME:PASSWORD@ftp.drivehq.com/