Recommendations on any working circuit that has at least 20 components
A 555 timer with a few blinking diodes or other shenanigans will easily make a circuit with 20 components, and lots of things there to analyze. There are literally thousands of YouTube video's, tutorials and resources to assist in your understanding of the circuit. Your school probably has all the required components as well.
Autoroute is a supplementary tool to route specific mundane connections, typically on boards with hundreds of components. You never autoroute an entire board.