"Content" menu item
In order to list of created pages, comments or if you would like to add a new page use "Content" menu item. You can creat/delete/edit/publish/unpublish your pages there.
Structure menu item
There are a list of existing blocks at this page and you can add, delete, disable or edit block by "Block layout" link under "Structure" link. There are two types of blocks: system blocks and your custom blocks.
You can add new fields to the site comments by clicking menu item "Comment types".
You can see the list of site contact forms by clicking menu item "Contact forms". There are two types of contact forms by default: user and site wide.
You can see the list of content types by clicking menu item "Content types". You can create a few content types for different needs with individual configuration and can create pages of each type in future, for example add different fields, enable/disable comments etc.
You can see the list of site menus by clicking menu item "Menus". You can add new links to menus or edit/delete them. "Main navigation" - main menu.
"Taxonomy" - list of vocabularies with tags. You can add tags to your pages in future.
"Views" - i will describe how to use views in future. Briefly, you can create pages and blocks that contains lists of users/pages/comments and filter them using view module.
You can setup a new theme or enable/disable/configure an existing theme by this link.
List of modules. You can add a new module or disable/enable existing modules, you can also find the link of module configuration for each module if they have ones. We had already used this link when installed "Admin toolbar" module.
Under this link there is site configuration pages i will describe these pages in details in future.
List of people registered on the site. You can add new people here or block/modify existing ones.
Site reports such as available updates, recent log messages, status reports etc.
Additional information about site modules