Partitioning drives on Linux is easier than on Windows. The default should even be enough, and even then, it tells you exactly what it'll do, so all you need is read.
If you want to fail, you need to do the following:
>don't read
>reject the warning
>confirm twice that you actually want to delete the other OS, despite the installer telling you that'll happen
>press the "save changes" button
>confirm again that the data will be PERMANENTLY deleted
Not even my dad has accidentally deleted anything. Aussie won't either