Charts and the table diagram
Charts
A chart is a Chart.js chart drawn from a view's live rows. Create the view first, then bind a chart to it and choose a type and refresh interval.
Mark a chart Public to embed it in a published page: in the Pages editor, use Insert chart… and pick it from the list. A chart that isn't public can only be seen in the dashboard.
The diagram
The diagram shows your tables and how they relate. Drag from one table onto another to add a lookup field between them. Click a relationship line to remove it.