You must have Oracle's Statspack package installed on the database in question.
If you do not have the privileges on the PERFSTAT schema, or the PERFSTAT schema does not exist, Toad will notify you when you try to open the Statspack Browser.
You can display up to nine charts at a time, in a three by three chart area.
The toolbar in the left hand side lets you work with the snapshots directly.
The chart list at the bottom left side lets you create new charts as well as display pre-designed charts.
Right-click on Custom and select New Chart/Grid.