Lock in Font Size

When I select a font size it won’t stay, reverts to something else. How do I lock it in so I don’t have to keep changing?

Please, edit (don’t answer) your question to provide more details. Read and follow these guidelines.

The Font and font size are set in the paragraph style you are using so the paragraph style First Line Indent for example uses Times New Roman 12 pt unless you set it for larger or smaller by right clicking and selecting modify in the sidebar. As long as you use that paragraph style you will get that font and font size.