How to use a binary tree to store a file structure?

Question

C++ / C#

Hello. I am doing a course project, the task is to store a hierarchical file structure in a binary tree. It is clear that the FS is also essentially a tree, where folders are nodes, but there is far from being a binary tree. What is the best way to store file systems in a tree? I write in C.
There is also an idea to store in subtrees, that is, the tree describes one level of the hierarchy, and the folder stores only a pointer to the subtree, but I doubt something.
Please help, I need ideas, I will write the implementation myself)