How to calculate?

#1
The book "Think Like a Grandmaster" by Kotov treats that question.
It is mainly a matter of mental discipline. Identify 3 candidate moves. Analyse their consequences one by one, evaluate, decide on your intended move, check it is no blunder. For efficiency think of each line once only.
Kotov surely knew how to calculate:
https://www.chessgames.com/perl/chessgame?gid=1084375
Hello,
so I've been wondering on how to get better at Calculation and I don't know which technique to use. Like how do you to it and how do you get better and how do you even do it?