The how is easy FFXIV is weird that the game does not require people to learn their role or job because for the most part they will be carried through normal content.
Which creates the weird situation that I feel is an intention of the devs to have the good players carry the bad players through the content but to not let the bad players know they are bad they tune the normal content low enough that even a bad player will buy the illusion that they are contributing to the overall encounter..
Legit run into people all that that state it is normal content relax.