XLogo is a Java program itself. This means you need to get a Java Runtime-Environment (JRE) or Java development kit (JDK) installed on a comnputer first. JRE is already sufficient for most people. You can download the latest version of Java from Sun Microsystem (http://www.java.com/en/download/index.jsp).
One you have JRE installed, it includes an application program called “WebStart”. This enables you to download and run Java programs on-the-fly using a computer with Internet connection. This is the easiest method to start Xlogo. After getting JRE installed, go to http://downloads.tuxfamily.org/xlogo/common/webstart/xlogo.jnlp to get started.
XLogo has its own documentation, located at http://downloads.tuxfamily.org/xlogo/downloads-en/manual-html-en/manual-en.html. This document also explains how to install Java and XLogo itself.