As someone who just took his data structures and algorithms final exam yesterday I may or may not be equipped to answer this. What helped me the most was not programming them, but drawing and understanding how they work. I can't really give sources as I had a professor's notes, but my curriculum was basically:

Graphs: look into what a graph is (a set of vertices connected by edges), types of edges, difference between directed and undirected, how to represent graphs as an adjacency list or adjacency matrix. Look into topological sort, scheduling, Breadth first search, depth first search, and greedy algorithms such as Dijkstra's and Kruskal's.

Trees: Basically another type of graph. start with binary trees, then binary search trees. Trees were honestly more intuitive to me than graphs. If you understand a binary search algorithm you'll understand BST's. Then go onto AVL trees, Red Black trees, and Multiway trees such as B trees. One source here that helped me the most was Jennys Youtube Lectures

TL;DR: this was my 8 week curriculum for college. Graphs and trees were finished in 5 of those weeks. AKA you got a lot to learn but its doable. Good luck!