You can easily update the stage as the deal progresses through its journey by following this instructions:
Click anywhere on the company card in the Deals view to open the company's Deal Flow CRM tab.
The current stage information of the deal can be viewed in the stage field (on the right side).
To select a different stage for the deal, click on the drop-down menu and select the target stage of that deal Only stages that are configured in your CRM will be visible.
By default, you will see the pre-set stages. However, the stages in the CRM are fully customizable. Read this article to know more about customizing the deal stages.