If Advanced Reports are not enabled, click
Reports->ChangeReportSettings->SwitchFromEssentialToAdvancedReports.
View the report you like, and click Customize.
In the Account tab, select which accounts you want to include. Make any other changes, and click OK.
To make this easily accessible in the future, right-click into the
reports and choose AddToFavorites. Enter a descriptive name, OK.
Alternatively, you could click AddToMyFavoriteReports in the left column.
You can later access that report with Favorites->FavoriteReports.