Reports can be found under "Visualisation" in the sidebar below "Themes".
From this page it's possible to view or create reports depending on your permissions within your organisations.
Some reports may be hidden, as they can be limited to selected teams and administrators.
It's really easy to setup your reports as they're using the same formulas that you're using on your dashboards. The creation and configuration of your reports is described in this support article: Creating a Report
It is also possible to create targets and promote selected rows of your KPI's when using Reports: Setting targets and starred
Once you've created your reports, you can export them as automatically generated spreadsheets and presentations, providing you with a quick overview of your most important KPIs and data: Exporting Reports