Navigate to Reports in the right hand menu.
Reports are grouped e.g. financial, staff etc. Click on the group to expand it to see all the reports within.
Most reports have a filter modal (pop-up) when you can make selections about the information that you would like to see. Make your selections and click "Run report".
Many report columns can be sorted by clicking on the arrow that appears when you hover over the column title.
Invoice numbers in reports can be clicked to show the invoice pop-up. When client names are hyperlinks, clicking these will open their client card.