Unfortunately, this tool does not support multi-page layouts at this time. We have plans to add it but don’t have an estimated release date.
For now, you can create two pages with the same styles (create one and then duplicate it and change the title and blocks therein), export them, then rename “index.html” in any of archives to another name, such as “about.html”. Then extract both archives in the same directory. Both pages will work fine. That happens because the style.css file contains styles of all blocks of a project and the sripts.js also contains scripts that you may need using Startup.