Documentation: many links broken in SUMMARY.md

[kristenmcd19]

Summary.md looks like a great resource for users looking to get a feel for the full list of functions provided by the project. However, many of the links in the page are broken leading to 404 errors, possibly due to a previous project restructuring.

While there are many helpful examples and video tutorial resources also available, for a person like myself who prefers at least initially doing a scan of text in one central spot before installing and diving in deeper, it'd be great to do a revision of this page and update these links or turn this into a central overview doc that surfaces the synopsis for each function or file.