In the WordPress admin, in the left admin bar is a "Settings" menu. Under that you will find a "Posterno" menu. When you click it, the first screen you come to is the General Settings for Posterno.
A variety of options are configured on this page, and this doc will cover each of them individually.
Posterno uses 7 different pages to process all the different parts of the frontend dashboard, profiles and listings submission. When you install Posterno it creates them for you, but you can change them on the General Settings page. Keep in mind these are simply plain WordPress Pages with specific shortcodes in them. If you want something other than the default, simply create it, put the shortcode on it, and choose it from the General Settings page.
Posterno uses a css framework called Bootstrap for styling all of the elements. However, each theme is coded differently and the quality of the code can vary. If you encounter any issue with the styling or if your theme already uses bootstrap you can disable the styling and scripts under "Settings -> Posterno -> Theme" in your WordPress dashboard.
If for any reason you wish to uninstall Posterno and remove all of it's data, you can enable the option "Remove data on uninstall?" so that when you delete the plugin, all of it's data are erased from your site's database.