How do you work with styles/presets in new Joomla version?

Since the upgrade, the headlines of my articles don't all match. Some are in the font I chose, and some are in the one that came with the original presets. How do I fix this?
Also, are there any samples of the various presets and styles (formats) that you can choose in the WYSIWYG editor box? For example, some of them have different line spacing. I would like to see what they all look like before choosing the one that works best for a particular article.
And while we're on the subject, why doesn't the Tab button work? I suspect this has to do with the preset style, but as I said, I can't tell what the presets look like without selecting text and trying them all out.
I guess this is three questions, but as you can see, I'm getting very frustrated at the inability to make basic formatting changes, as you can in a word processor.