Best resources for understanding more about data trees?

I’m becoming more comfortable with grasshopper and its data trees, yet I still find myself guessing as to whether something needs to be grafted, flattened, etc.

I’d like to understand data trees more. I found a course by ThinkParametric that is all about data trees that I plan on completing later. In the meantime, are there any other good resources you can point me towards to help with my understanding?

I appreciate any input. this series by David Rutten

I liked This bookby Arturo Tedeschi. It covers some topics on theoretical part (including trees), is written in “easy to read” way and has some step-by-step grasshopper examples. When I began my adventure in gh and struggled with some harder parts like data trees it helped me a lot. It takes some time to get through it but it’s defienately worth it when I look back.