Buddha was not a Buddhist. He was someone who realized how much he, and the rest of humanity, suffered; and he decided to figure out a solution. Buddha discovered, or perhaps rediscovered, insight meditation, and used it to free himself permanently from suffering. Insight meditation, also called Vipassanā, meaning insight into reality, is a very simple form of meditation in which you pay attention to the sensations on and inside your body, from moment to moment and with equanimity. Equanimity is when you don’t push something away or crave more of it; you just let it be as it is.
Everything that you perceive through your senses causes some kind of sensation to occur in your body. Some perceptions result in pleasant sensations and other perceptions result in unpleasant sensations. At the deepest level of your unconscious mind, you are continually paying attention to the sensations, grasping at the pleasant ones, and their associated experiences, and resisting the unpleasant ones, and their associated experiences. This is suffering: unconsciously reacting with craving and aversion to stimulii. When you start practicing Vipassanā, you start to realize the extent and depth of this suffering. It is continual and all-pervading.
By consciously scanning your body for subtler and subtler sensations, and consciously being equanimous with them, you can retrain your unconscious mind at the deepest level to not react with craving or aversion, to stop suffering. When equanimity is fully habitual, there is no more reactivity, and no more suffering.
The sensations that arise in reaction to perceptions are energetic echoes from the past, from when a past situation was reacted to; they are impurities in the mind that cloud perception of reality. When these sensations are allowed to arise, and are not reacted to, they can pass away naturally. When you unconsciously react, you maintain these impurities, and lay down more of them.
With regular practice of Vipassanā, not only do you get increasingly skilled at being equanimous and non-reactive, which becomes unconscious and automatic, but you also purify your mind so there is less to react to. External situations still arise, but the perception of them results in increasingly less intense internal sensations. You become less disturbed by life, less reactive, and your suffering begins to end.
While there are now so many complex forms of Buddhism, with intricate rituals and practices, Buddha wanted to keep it simple, to teach this simple technique to end suffering. It’s best to learn Vipassanā in an intensive retreat, where you can really see the benefits and establish your practice. I highly recommend the ten-day meditation retreats taught around the world by S. N. Goenka, where food and lodging is free to you, paid for by past students. These retreats are one of the best ways you could use your time, and will significantly change your life for the better.