how to resolve Camunda coding challenge

A few months ago, I applied for camunda for internship and as part of their application process, they propose to me to complete a quick coding challenge within 7 days.It should take around 2 hours

the goal of the excercise is to build a small java application which connects to the camunda REST API , fetches a diagram , finds a path from start node to an end node in the diagram and prints the IDs of all the flow node on the path to System.out .

This is the link for excercise: https://docs.google.com/document/d/1g2O9naG1eek_e_QfORZceT3-rAEpmZpWYcgjf7cBB1Y/edit#heading=h.2ikfgy94df2i

the exercise is well explained and it's easy because the algorithm is simple and I have already learned the (basic + Advanced) in Java, unfortunately I didn't succeed the exercise. But even after taking other courses in Java I still not able to complete the exercise.

Can someone help please with this coding challenge ? Any help would be appreciated