Now that you deleted the sample comment, post and page, you will do the same for some of the plugins, that by default are coming with the WordPress installation, however you are not going to use them.
Plugins are small extensions for the WordPress platform, and they are very useful when it comes to customizing your WordPress site functionality. Later on you are going to install several plugins, where each one of them will provide a different function for your site.
From your Dashboard go to Plugins and click on Installed Plugins, than check the boxes next to the
Jetpack by WordPress, MOJO Marketplace, Sidekick, and WP Super Cache
From the BulkActions menu, select Deactivate, and click Apply.
In the next step, you will install a theme for your website.