If you have more than one project that you'd like to analyze with a report, simply select those projects (as well as the report) and click the Analyze button. The results on the Scoring Analysis page will list each Report Name which will link to detailed results.
If you have a collection of projects that you typically need to analyze on a regular basis, you may choose to group these in a Project Set. To do this, check the projects you would like to group together, right-click on any of the selected projects, and select Create Project Set From Selected from the context menu. You can rename this Project Set to something meaningful. When you want to analyze all of the reports in the project set, select the checkbox associated with the project set (as well as a report) and click the Analyze button.