Hi laurakaz,
This is a funny one to get stuck on, I know, it caught me too when I first started on WordPress and Graphene.
Just under the Add Media Button at the top of your Post Page are the symbols for Bold and Italic. Just under those is a drop down box. Its default state is “paragraph”, but if you use the dropdown, you’ll find selections for Heading 1, Heading 2 etc. up to Heading 6. You can use these to change the size of your text in the content section of your pages and blog posts.
I know you said you know nothing about html, but it’s actually quite easy to change it with html as well if you don’t want to use the Headings in the dropdown. You can do this in the page section itself by changing the view from “Visual” to “Text” and then changing the html attributes for the font that you wish to change. There’s a very easy tutorial on html and font at W3 Schools here.
Hope that’s what you’re after. 🙂
Regards,
Sharon