Since it's for testing purposes, it doesn't matter which application you choose, but the question still arises why you would want to create a script for installing CCleaner, which you can simply install silently by supplying the right parameters? Just wondering. I don't know much about making addons since I make my own silent installers for HFSLIP, but you'll need to compile the script for starters. You'll have to make an ENTRIES.INI-file to install your addon. See here for an example. Also, download some of the pre-made addons and see how those are built, that should help you enough I believe to be able to make your own addon. I don't believe that you have to, but see the link I posted above, download one of the pre-build addons and have a look. I believe you simply have to add all the files to one folder and use the before mentioned INI-file to install your addon.