The Content tab of the dashboard designer is where you choose the reports to include in the dashboard. Once you add a report (or reports) to the dashboard, you can configure each report's filters and, if applicable adjust date/frequency settings for time series reports, resize/rearrange, or remove the report from the dashboard. In addition, you can decide for which reports, if any, you want to allow dashboard consumers to change filters and/or time series settings when viewing the dashboard.
The Available Reports section displays the reports that are available for the dashboard that you are permitted to access.
Note that both the General and Available Reports sections are collapseable, so you can put one or the other out of the way to increase screen real estate. Remember also that you can resize the Preview Pane.
Once you enter a title (or use the default) you can move to any of the other tabs by clicking Display, Scope, Team. See also Using the Dashboard Designer (Beta) for general information about the dashboard designer.
Adding Reports to a Dashboard
The Available Reports section displays a filterable list of all reports you (the current user) have access to. An ad-hoc filter at the top of the list lets you develop new/use existing filters to fine-tune the list of reports. You can also control which columns to display in the Available Reports section by clicking the gear icon to open the Configure Settings dialog, where you can rearrange the fields you want to show or remove from the section.
The screenshot below shows the Available Reports section - note that the view was adjusted to expand the left side of the tab by grabbing the resize bar in the middle of the window and dragging to the right (shrinking the Preview Pane):
To add a report component to a dashboard:
Use the ad-hoc filter to show only the reports you are interested in.
Simply move the report(s) to the Preview Pane using one of the methods described to the left:
Use your cursor to move/rearrange/resize reports. Their size/placement will persist once you save.