Can't add blog to site w/ static front page; existing posts don't solve problem

I need to add a blog to a WordPress site with a static front page. It’s version 4.2.2 with the free version of the “discover” theme; I think the theme may have been modified by the person who built the site, who is not me and who is not available to solve this problem.

I followed these instructions to add the blog, but discovered that there was no page listed as “home” in the pages listing. So I left the “home” page unassigned and designated “Blog” as the “posts page”, but that just meant the blog became the front page, which I didn’t want.

I went digging for the home page (which I figured has to exist, since there is definitely a front page), and couldn’t find one. The closest I got was under “Theme options,” where “Blog display” was set to “off” and the homepage text was in text boxes labeled “Homepage Box 1 text”, “Homepage Box 1 thumbnail image,” etc.

So if there isn’t a real front page—just a collection of text boxes as part of the theme—how do I set up a blog on this site?

Site is here, for what that’s worth.