The first thing you see when you access WordPress admin panel is the WP Dashboard. It is a collection of gadgets that provide you information at a glance so you do not have to navigate through different pages to get it. In Other word it is a collection of what you see in Admin page. For example, you can see the new comments, make a quick draft post, see the latest WordPress news and more.
To configure which content (Information) you want to see on your Dashboard, click on the Screen Options button at top-right part of admin screen. It will expand a panel that will allow you to check and un-check the different information section you want to display OR hide.
Once you have the gadgets you want to use displayed, you can rearrange them by simply drag-and-drop them around your screen. Note that since Your WordPress admin panel (Dashboard) is responsive. This means that depending on the size of your display you will see different number of available columns for your screen or widgets.
In addition, when you install some plugins, some of them may provide you self additional Dashboard gadgets to use.