You want to place a video from the internet to your desktop. what process do you use?

If you want to place a video from the internet to your desktop you use the process of downloading. The term downloading describes the process of getting/receiving content from the Internet on your personal device,  more concrete from a remote system, which is some server (web server, an FTP server, an email server..).
Downloading is the opposite process of uploading, where you send (upload) data from your computer to the remote server on the web.

Lymphocytes must recognize antigen and respond to another signal generated by microbial infection to become activated.