A computer analogy for the brain works to some extent but our brains are so much more complex and work differently than the best computers we can make. Yet our brain is the thing that has thoughts and memories and ideas and it also controls our body and uses the body to sense the world around us. Our brain is inseparable from our body.
The brain is incredible because unlike a computer, it programs itself. Starting out life as a new born baby, the brain is already there and ready to go but it is not programmed for life. The new born brain is programmed to learn.
Up to the age of two the human brain grows many millions of connections as the baby explores the environment. As the toddler changes into a child, the connections that are really useful to it are strengthened and the others lost. As the child approaches its teen years, yet more connections grow. During the teen years and into the twenties these connections are also refined so that the ones which the person finds most useful are retained and many lost.
After the mid-twenties the brain is complete and ready to work, explore, invent etc. Yet even then the brain still adapts itself as new experiences are encountered. The brain constantly changes throughout life. That is, if you exercise it.
To get the most out of your brain, keep it fit and give it plenty to do.