The Easy Site Builder is also known as Site Pad and can be found in the "Software and Services" section of the CPanel X3 theme under Site Pad.

In the Paper Lantern theme you can find the Easy Site Builder under the "Software" section and is called Site Pad.

The name is changed to Easy Site Builder time to time so if you do not see the the Site Pad name and icon, just search for Site pad. If you can't find Site Pad or Easy Site Builder, than you might not have it on your Cloud. You'll than need to have support move your account to the right place that has it available.