Hello :)
Please refer to this video tutorial which I find very helpful and gives you an example how to work with Tree node: https://youtu.be/kqajl-g5Lo0?si=i8piHc-O4rBIuwZf
The documentation can be found here: https://docs.mendix.com/appstore/modules/tree-node/
In case you think I helped you somehow, please mark the answer as accepted or let me know in case you need more help :)
Kindest regards!
Fjordi