I can help you open your reports in multiple windows, @deirdrelubbe-gma,
To do that, simply go to the Reports menu and find the report type you want to use. Then, right click on the report name and select Open link in new tab or Open link in a new window. Your browser will automatically open a second window so you can work on different pages at the same time.
Also, I'm adding some resource links to help you with the reports and other tasks in QBO: