You need to do your own thinking. Why? Because that is what it means to be human. Don’t know how? You are not alone. Schools don’t teach thinking, because it cannot be standardized, and because a thinker cannot be controlled as sheep.
Here are some methods of thinking, in bold strokes:
One would think that if you sit by yourself and use the mind to reshuffle all the information you have consciously or unconsciously gathered, then you can do effective thinking, an maybe some people can, although the methods of doing this kind of thinking require a lot of writing.