Basic Way to Learn Openings In Chess

LEARNING AND STUDYING CHESS OPENINGS 

What is the difference between theoretical and setup based chess openings?
In a theory based opening, you cannot play the same way in response to the opponent's moves. Setup-based openings are traditionally set to be openings that don’t really have counters or defense mechanisms. 

THEORY OPENINGS: Caro-Kann, Sicilian, Scandinavian

SETUP - LONDON SYSTEM, KING’S INDIAN

Define theory and novelty. 
Theory in openings are positions that have already been explored. Novelties are the first moves out of those theories or openings. 

How do you use an opening database?
When you look for an opening, find it and choose one of the most popular versions or lines of the opening. It may not be the best, but a computer evaluation will help you. Also, you don’t always have to play the best or most popular theories. You can learn non-traditional openings to throw opponents off. 

FOR EXAMPLE: Gambits, Caro-Kann, Dutch Defense, Budapest 

Also, you can use the analysis to review your openings and see if your moves line up.

BEGINNER: Learn a gambit with either color and learn the second or third lines of popular theories. 

INTERMEDIATE: Add a layer or a variation in your openings. Make it an uncommon or trickier line to better understand the opening and your position. If you lose a lot to a specific opening, find a way to counter it. 

ADVANCED: Master the most important and popular lines of the openings. Implement the most unconventional openings to your repertoire. These may come in handy for bullet chess.