Once the program is installed it will integrate in the 'shell' of your operating system. To send a document you only have to right click on it and select the option 'send to kindle'. The window of the program will directly appear and you can choose the name and the author with which you want to send the document.
The window of the application will also inform you of the size of the document and the device where you will send the file, although you normally only have one Kindle, of course.
Send to Kindle is an incredibly useful tool for users of the famous Amazon e-book because thanks to it downloaded books and text documents can be send from your computer in a matter of seconds. The only thing you need, of course, is a connection to the Internet.