Many books and publications about transistor circuits have titles like...
Put these books to the side for a moment. Because if you want to understand the transistor and its circuits, you should first understand the three basic transistor circuits...
Find out how a transistor, or more precisely a bi-polar junction transistor (BJT) can be connected. For this purpose you build the circuits and get to know the most important features.
In the further course you build transistor circuits with more transistors, and you realize how these circuits can be traced back to the basic circuits.
Before you can start with your first transistor circuits, you need to make a few preparations...