Starter SPA issues

I installed this theme locally, and I ran into a few problems. When I click one of the WordPress admin links at the top of the page (Customize, Edit Page, etc.) I get “404/Not found”. The URL appears in the address bar, and I have to position the cursor in it and hit enter to open the link. Whether I’m logged in or not, when I type the site URL into the address bar, it opens on the 404 page, and I have to click one of the menu links to see the page. I have it set up for a static home page, by the way.