Buddhists view everything as a sum of parts - a car is not a car, it's a collection of wheels, engine parts, transmission parts, etc. In Buddhism, you are not "you" - you are just some organs working together. Likewise, when you sit quietly during mindfulness meditation you learn to identify sensations of pain and discomfort as things that occur outside of you, you just perceive them. In other words, there is no you, there is a sum of parts that you have traditionally perceived as you. If you decouple yourself from these sensations, you can no longer be hurt by them.
Keep in mind that Buddhism is deeply rooted in a time when the only way to avoid suffering was to ignore all desire, because it wasn't going to be fulfilled anyway. So, if you want a primer course on Buddhism, read the "4 Noble Ways" and "The Eightfold Path" (about a 30 second read for both) - while these sounds esoteric, they basically summarize Buddhism in a very clear, concise, and logical way; which is that Buddhism is nothing by asceticism and a way to let go of wordly desires and ignore the outside world, to ease suffering.
Everything else is fluff by pseudo-intellectuals who will flood below this post.
As a side note "Altered Traits" was a useless, garbage, author-self-promotion book with no actual info, thanks for nothing HN.