Nodes are the points on each "entity" you create. The node tools will allow you to manipulate the entities you create to exactly what you want. I haven't watched any of the You tube videos, so no idea.

Custom symbols will allow you to make maps more akin to Dundjinni than the old CCII type maps.

Layers are the tool where you can divide up "entities" that you make. Water, streets, text, vegetation etc etc. My map has about 40 layers on it. Sewers, dwarven stronghold levels, buildings, burnt buildings, wells, sewers, street names yadda yadda yadda. If you start off with good organization to start, it will save a ton of headaches.