Hi David, Categories are usually added at the very top of a profile, (although I have seen some added at other places).
For a cemetery in the United States, the correct way to categorize it would be: the name of the cemetery, COMMA, the city (or county or township if appropriate), COMMA, State. Example: [[Category: Lake View Cemetery, Seattle, Washington]].
It looks like you live in the USA, so the best thing to do would be to go to the US Cemeteries page, then click on the correct State, and then the County within the State. Check to see if the cemetery you need is listed. If it is, just copy the complete category name at the top of the page, including Category, and put it on your ancestor's page, within double brackets, as shown above. (Be careful, as sometimes a cemetery has several names. We usually use the name used on FindAGrave unless that is a reason not to.)
If your cemetery isn't there, you can set up the cemetery categorization yourself. Look at the page for Cemetery Formatting. If you still have problems, post a question here, and be sure to add the Tag: Categorization.