OPENING THEORY

I am new to chess study. Please guide me on how to study openings. I want to study Scotch game and Sicilian Alapin but don't know how. Also I have come across a word "Repetoire" many times . What is an opening repetoire? Please reply. I would love to read a detailed one.

https://www.chess.com/forum/view/chess-openings/what-does-a-repertoire-even-look-like-1

Consider this 2005 GM Nigel Davies quote:
"The way I suggest you study this book is to play through the main games once, relatively quickly, and then start playing the variation in actual games. Playing an opening in real games is of vital importance - without this kind of live practice it is impossible to get a 'feel' for the kind of game it leads to. There is time enough later for involvement with the details, after playing your games it is good to look up the line."

https://www.chess.com/article/view/picking-the-correct-opening-repertoire
http://chess-teacher.com/best-chess-openings/
https://www.chess.com/blog/TigerLilov/build-your-opening-repertoire
https://www.chess.com/blog/CraiggoryC/how-to-build-an-opening-repertoire