Most of the time you work in model space, where you create your map on a 1:1 scale. You can create multiple paper space layouts, where you can place a title block, include several views of the same item, and include notes. Switch between model space and layout spaces using the tabs at the bottom of the application window.
Model and Layout tabs
By default, each map has one Model tab and two Layout tabs. Create more Layout tabs if you need them.