A name is written from the specific to the general; the tree is walked from the root downwards. Every suffix of the name is a domain, and every domain is a node of the tree.
level 0 / 0
The name each colour is one level of the tree
Try:
← written: from the specific (left) to the general (right)the tree: from the root (the trailing dot) leftwards →
The same name in the tree the path from the root; other branches in grey
Click any label, bracket or node to jump to that level.