Setting date range

You can set the period for the reports by clicking 3 Months to reveal additional options:

Data Period Options
Data Period Options

There are additional options under the To-Date tab:

To Date Options
To Date Options

Individual insights

All insights on the page by default will have the date range set for the page, but some graphs have their own to and from date-pickers to select a range just for that graph:

To/From Date Pickers
To/From Date Pickers

Also, in time-based graphs, you can click and drag in the graph itself or click and drag the start/end handles on the timeline below the graph to select a smaller range: