The first thing we will do is to get the Ejs program. Click this link to open the Ejs web site.
From the "Program and documentation" section click the "Easy Java Simulations 3.4" link. Save the zip file to the desktop. When the download is complete right-click on the zip file and unzip it to the desktop. That will create an "Ejs" folder for you on the desktop.
The other thing we need to download from the Ejs site is the "Manual for Ejs 3.4." Right-click on the name and save the manual to the Ejs folder.
Optional: two other things that you may find useful are the Appendices to the Manual, and the HTML reference pages, in the compressed version. If you get those they should be saved to the Ejs folder, too.