To Create Category pages all you need to do is write them on a character's page under the "Categories" section. Doing so automatically establishes a section for that article and others like it with the same name, it's why there has been so many repeat categories actually. Careful though if you use different capitalization or spacing it makes two different categories, like if you put "Evil Clone" for one character and "Evil clone" on the other it would make two different category outlines. Once the category is established on that character, publish the change and click on the new category at the bottom of the page, it will take you to a newly made pre-category page with a list of all the articles with that page attached. Since you will have just created it, there will be no description so just hit the "Create" option on top to start adding a proper definition of what you are trying to make.
Because there is no way to curtail people making duplicate categories or uneeded ones ahead of time the admins here have made a no new category rule to prevent abuse though, so make sure to get their permission before trying or else it may be deleted.
You can use your native speech if you like, I can use Google Translate.
The easiest way I have found is to go to the category page, right-click on the articles listed and "Open New Tabs" to them, as many as you are comfortable with at a time, and then edit the pages. There are 2 edit modes now, in "Classic Edit" the Categories will be on the left side of the edit pages, On the New Standard Editing the Categories can be seen by going to the little slider bar on top of the page next to the "Cancel" button. Either way once you find the categories on the editing page hover over them until you see a tiny garbage can icon, click that to delete them.
Once you do that and publish the changes you can refresh the main category page you opened the tabs from and the articles will be removed.
Yeah, hello. Sorry, I have made an error. It's about the villain "Alpha One" for TMNT. I has adde a page about him without know that he was already on wiki. Forgive me for my error, it wasn't my intention.