Also, since this is for school, maybe ask your teacher?
My teacher isnt allowed to help, Im having trouble with where to start with the algorithm, with regards to connecting nodes and how to identify each node and their cost.
A*‘s job isn’t to connect the nodes; it’s already given a connected, weighted graph.
Again: A* is extremely documented. Wikipedia even has pseudocode. Have you looked it up and gotten stuck? If so, where?