If you really can't, you should get familiar with how data can point to other data, it is fundamental and done all the time.
It's easy to make an imbalanced binary tree.
I once decided that building a binary tree based only on a friend's explanation of how they worked; it seemed like it would be a good learning exercise for myself (I don't have a CS degree). It was like 10 minutes of coding to get it minimally working & tested, but then I had to work out all of the different rotations to make it a balanced binary tree (I don't know that an imbalanced binary tree is ever actually useful, as it could just work out to be a slower linked-list in the worst case scenario).
I did it once, took me a little while, but I don't know that I could do it again without having to reexamine all of the different cases that result in imbalance and the rotations that respond to each.
If the current node is a leaf, insert left if smaller and right if bigger.
If not a leaf nods, run the method recursively on the left it it's smaller, on the right if it's bigger.
If they asked you to write a self-balancing binary tree it's one thing, but there's nothing tricky about writing a normal ordered binary tree.
[data, *next] [data, *next] [data, *next] [data, *next]