i'm trying to separate categories/subcategories in author.php so they each have their own endpoint link.
It's very similar to this question BUT for the life of me I can't enable the plugin provided: How to set up sub-categories for author pages?
The solution provided was this: https://gist.github.com/705545
I've downloaded the file, it's instructions say "enable this plugin" ... but when i put it in wp-content/plugins folder it doesn't show up on the list. I've tried putting it in a folder, and just putting the .php file in plugins folder. But it doesn't show up on the list.
How can I enable this? or if you have any other ideas on how to achieve these results i'd greatly appreciate it.