How do I insert text in the middle of an image?

As you will gather from this question I am new to WordPress. I’m trying to work through Tyler Moore’s Tesseract tutorial so that perhaps I’ll be able to build my own responsive website. But I’ve reached an impasse half way through. I have a graphic theme on my Home page but I can’t insert text into it. I have the SiteOrigin Visual Editor activated and think I’m using it correctly. But when I insert text it always appears beneath the image. What magic can I use to position the text in the image?