Creating blogs in editor and adding pictures

Hi all,

I am an editor, not a designer, nor am I a coder. I have my site set up and I am adding my blogs. I saw a + sign to add a picture, It was hard to find it. But seems I can only add one picture? How to I add several pictures?
My website is live, I don’t have a sample to show.
www.helpadmin.com.au

thanks for helping me