BuddyPress.org

@timostr79,

The BuddyPress pages that you are making reference are automatically available when components are selected. In order to reach these pages/directories, you will have to set up (create) “Navigation” menu items. To assist you with this task, read through the following documentation:

Navigation menus

As to previews, this is available from the wp-admin area via the customizer (Appearance > Customize)