sftp is an interactive file transfer program, similar to ftp
type help at the > prompt for a list of all the commands
put to send files from local machine to server
get to grab files from server to local machine
For details see man sftp
Alternatively you can use a GUI program like Fugu or FileZilla or WinSCP for Windows to do this.
When connecting from outside the UCSD network VPN is required. Click here to learn How to VPN into the UCSD network.