When you hear computer computer scientists talk about processors you might hear them describe processors as the “brain” of the computer, but that is not the case. Instead, to properly understand what a processor does, you have to think of the entire computer as a brain, and work from there.
The processor’s job is to take an instruction from memory, perform that instruction (doing math, writing to memory, ending signals to other computers, etc), and find the next instruction. Processors have to do all of this quickly, and by quickly I mean billions of times per second quickly. Processors can also be split into multiple cores. Each core is capable of performing tasks independently from one another. Think about a factory with workers assembling a product. The processor is the factory, and each core is a worker in that factory fully assembling a product from start to finish. The more workers, or cores, there are the faster the factory can produce products. Cores work together in parallel to take lines of work, called threads, and generate some sort of output. Threads are all put into a queue, and each time a core finishes a thread, it will take a thread from the front of that queue and begin processing that thread. Likewise, if the end of a thread does not fully complete a task that a program needs to finish, then that thread will create a new thread that performs the next task that a program needs to finish and put that thread at the end of the queue.
Do note that there are a two tasks that a brain can accomplish that processors do not accomplish. First, processors are not used for either long or short term memory (OK, that’s a small lie, but the memory that processors have is incredibly tiny and temporary). Second, processors do not determine what tasks they should be doing on their own. They rely on other components to send commands.
Knowing this, I hope you can appreciate the more complicated intricacies on how computers work.