To copy a file from an FTP server to the flash of a ASA you could do the following:
Which will then prompt you for all the details (username/password/location/file). But there is a better way which will allow you to put all of that information on one line.
To indicate all of the details on one line you can do:
This indicates the username is
ftpuser, with the password of
Passw0rD with the location of the ftp server at
192.168.5.50 with the filename