The 'how to install' is in the left under 'quick links' at appstore.mendix.com
I think the help file for this module should be expanded with this information:
This app will create a seperate module in your application. To incorporate this module into another module go to the images and move all the images to another module. Furthermore move the CountryToString flow and the StringToCountry java action to the same module. And do not forget to change the java code and insert the module name in the NEWMODULENAME place (see example) // BEGIN USER CODE
try {
return NEWMODULENAME.proxies.Countries.valueOf(this.value).toString();
}
catch (Exception e) {
Core.getLogger(this.toString()).warn("Invalid country: " + this.value);
return "";
}
// END USER CODE