Greetings davidk,
AdwCleaner is a portable software. This means that no installation is required in order to use it. You just have to launch the previously downloaded executable that you can find on this page : https://toolslib.net/downloads/viewdownload/1-adwcleaner/
If you don't understand something, here is the english documentation : https://toolslib.net/forum/viewthread/182-en-adwcleaner...