Read More link not showing up

I just started a WordPress blog. I’m not the most computer savvy so I’m learning as I go. My last step is including a Read More tab so that a reader can click at the end of an exerpt and be brought to the full post. I have added the Read More plugin. It seems like it should be very simple and yet it’s not working. I am so frustrated because there doesn’t seem to be a place to call for help. I am using the SimpleResponsiveBlogily theme.The only option I can find is to click the plus sign and then click “more”. I get a box to come up that says “Read More” but nothing happens when I look at my actual post. Any help would be greatly appreciated.