The eirt program is available for download at http://sourceforge.net/projects/libirt/files/eirt. The installation program is named eirt-1.0.0.exe where 1.0.0 is the version number.
The installation program first ask to select the installation language. Select english and click on the ok button. If another language is selected, it will also be used in the program. It is possible to change the display language after the installation with the settings tools(see the chapter 4).
For the rest of the installation, you can keep the default value. Near the end of the installation, an Excel macro is run to install the program into Excel menu. It is necessary then to accept the macro activation.