Containers are the layout
A dashboard is built from horizontal and vertical layout containers. Horizontal groups items left to right and lets you set all their heights together; vertical stacks them top to bottom and shares their widths.
Use the Layout pane and the item hierarchy to see what's nested where. Dashboards that resize badly are almost always dashboards where things were dropped as floating objects instead of into containers.
Sizing
Fixed size guarantees the dashboard looks identical everywhere — the safest choice when you know the target screen, and the best for consistent PDF export.
Automatic stretches to the browser window, which can leave charts looking sparse or cramped. Range sets minimum and maximum bounds and is the usual compromise.
If people will view on phones, add a device-specific layout rather than hoping the desktop version reflows sensibly.
Actions
Actions connect sheets. A filter action uses a selection in one sheet to filter another — click a region, the detail table narrows. A highlight action dims non-matching marks without filtering. A URL action opens an external link, optionally passing field values as parameters. A parameter action sets a parameter from a mark selection, and a set action updates a set — those two unlock most advanced interactivity.
Set the source sheet, the target, and whether the trigger is hover, select, or menu. Hover is tempting but gets annoying fast; select is usually right.
Restraint
A dashboard answering one question well beats one answering six poorly. Aim for a small number of views, a clear reading order (top-left first), and consistent colour meaning across every sheet.
Every filter you add is a decision you're pushing onto the reader. Sometimes that's the point; often a well-chosen default is more useful.