How to study openings?

I know how to study openings but I need yall's help to explain it because my friend wants to learn chess lol

Do not study openings, just play and analyse your lost games.
Study of endgames is far more efficient.

There is one typical mistake made by many players - they simply learn the opening moves by rote. But as soon as they are out of their preparation, they no longer have any understanding of the position which has arisen. Even more important than learning specific variations is understanding the typical middlegame positions and being familiar with the correct plans. Study games by strong players and find for yourself some model games which illustrate important plans or ideas in the opening and the middlegame.