When adding a category, if you find that an LGBT tag is not supported by the text of the article, you will need to add this information to the article. One easy way to do this is to create a personal life section, which is typically placed at the end of the article's main text. In this section you can talk about the persons openly proclaimed identities, as long as you provide a reliable source that shows they are publicly out (in the case of living people). To create a new section simply select heading from the style drop down in the visual editor and type out the section name.
When you write about someone's personal life, including their sexual orientation or gender identity, you need to add a citation to document this information and to confirm they are publicly out. To add a citation in the visual editor simply click the cite button along the top to insert a footnote where your cursor is. You can do an automatic citation if you have a link or ISBN (all books will have one, usually on a front page), or click manual to type in the citation information.