Click a link. If the page looks like a plain file list (no logos, no CSS, just hyperlinks), you have succeeded.
If you successfully use the intitle index of method, you might find several legendary themes that are no longer available on Microsoft’s website: Intitle Index Of Windows 7 Themes
Open the link. If you see a list of .themepack or .zip files, right-click and inspect each file’s size and last modified date. Prefer files from 2012-2017 (peak Windows 7 era). Click a link