Tableau dynamically resize container

1. How do I resize a container in tableau?
2. How do I set tableau dashboard size to automatic?

How do I resize a container in tableau?

Under Objects on the Dashboard pane, select Horizontal or Vertical. Drag the container to the dashboard.

How do I set tableau dashboard size to automatic?

Actually, Tableau sets all dashboards to be a fixed size by default. In the sample dashboard below, on the left side there is an option called 'Size'. The drop-down box here provides the opportunity to set your dashboard to the screen size that you will expect your users to use when viewing.