using filezilla for amazon ubuntu server

when you create ubuntu instance on amazon ec2, you will get user name(say, root or ec2-user) and one .pem file
then in your local ubuntu, you can access the server by:

chmod 400 xxx.pem    #make this file publicly visible
ssh -i xxx.pem ec2-user@xxx.xxx.xxx.xxx  


# xxx.xxx.xxx.xxx  is the ip address amazon assigned to you

thus you can access the ubuntu server on amazon.
however, for transfering files between local machine and server, we usually use filezilla.
the default internet access directory is  /var/www/html  however, the general user do not have rights to upload files directly to this folder, so we can:

sudo chmod 777  /var/www/html 

thus we can use filezilla to transfer files directly to that folder.
after installing filezilla, we should configure first:
1)open the site manager->new site. then we name it as something you like, and for host, input the ip address, for port:input 22, for protocol: choose SFTP-SSH file...    for logon type: normal   for user: input your user name
2)edit-> settings->connection->SFTP, press: add keyfile. thus select your pem file, and  will convert it to ppk file.
after that, back to step 1), press "connect", then your local machine would connect to your amazon ubuntu server. You can now use mouse to drag files from your local machine to the server and vice versa.