Library call

Hello to all, and I hope that everyone is safe with the actual health pandemic.

I want to use the Velleman VMA450 LCD I2C Library arduino library ( at the bottom of → Downloads – Support – Velleman – Wholesaler and developer of electronics ) and understand the details of the algorithm.
The example “HelloWorld.ino” file make a call at the very begining with the #include <LiquidCrystal_I2C.h> and on it it’s a complete list of #define XXX 0xhh. This #define’s are used in the file .*cpp of the library set.
My question is: in whitch moment this .*cpp file it’s loaded in order tu use the functions on it? I don’t see in any part something like include LiquidCrystal_I2C, even in the .h file. If someone can giveme a clue about this code structure question I well be very thankful.

LiquidCrystal/
-/examples
-keywords.txt
-LiquidCrystal_I2C.cpp
-LiquidCrystal_I2C.h
-README.md

Thanks in advance.

I found the answer here --> https://www.arduino.cc/en/Hacking/LibraryTutorial

The magic of the open source!