At first, you can take cultivating interest as an introduction. At this time, we can look at Sophie's World, a good philosophical enlightenment reading.
After that, you can read Russell's History of Western Philosophy and Feng Youlan's A Brief History of China's Philosophy.
Many times, when we understand the development process of philosophy in human history, we will be surprised to find that many of our existing philosophies are actually only at the pre-Qin level in China or in the ancient Greek period in the West. It is hard to understand if we start to study Locke, Rousseau, Kant, Hegel and Marx at once.
Therefore, starting with the development of philosophy, to see how human thoughts evolve and develop bit by bit is to improve your philosophical level.
After reading the above books, it is not too late to choose your own philosophical schools and viewpoints for in-depth study.
Finally, I wish you happiness!