Hi Laurent
Your current predicament reminds me a lot of when I started playing Go.
I’ve been writing a series of 19X19 FOR BEGINNERS articles with readers like you in mind - trying to break down the various concepts, tactics, and general strategies of the game into something a beginner can understand.
I know it’s a lot of reading, but take your time. There are days/weeks of reading here, so please digest these articles at your own pace - and hopefully these will help you progress through you first 100 games faster:
Introduction: Making Sense of Go
Part 3: Playing a Balanced Opening
Part 5: The Stages of the Game
Good luck!