I don't mean to be a dick here but most of the classes are relatively straightforward unless you literally have never played a party based RPG in your life.
The mechanics behind how everything works and what everything means it what is challenging for a new player.
For example
What is special about a heavy weapon?
What is advantage?
What is proficiency?
or at least these are some of the things confusing for me as a person who doesn't play D&D
