How to learn a new programming language or a new technology in a short period

First of All, you need to use divide and conquer strategy, for example, there is a car and I want to learn how this car works, so it's better to divide the car into pieces, first I learn how the system of the engine works, second how the electrical system and electronics work, third what is in the interior in the car… The main idea is to go step by step which means you shouldn’t try to understand everything in one shot because you can’t .