Building Custom Plugin with Dead Link Deletion Feature

Hi,

I have never built a WordPress plugin before, so I am not really sure where to start. The first feature I want to add is one that displays a button beneath the heading on single posts that allows users to delete the post if it links to a page that returns a 404 error. This feature is going to be used on aggregators and is intended for instances in which an article is removed from its source.

I have done this in the past by altering themes, but the way I did that depended on functions within the theme. I no longer use those themes and want to achieve the same result using a plugin that I can install on any site.

The next phase will be to add options to restrict which posts display the dead link removal button. That will be done by category and source URL, so if I only wanted to make that feature available for certain categories or where the source is from certain domains I could do that without it impacting other posts.