I'm probably the wrong guy to ask, but I'll try.

The principal comes down to the idea of impermanence.

Nothing is forever. Not the good, not the bad, not the meh. Change is impossible to prevent as well. At most, you delay change.

As you learn to stop holding on to any given moment, instead living it, the edges get worn away. This doesn't mean that you don't experience pain, stress, dissonance; you do. But you learn to accept them as temporary and abide as they flow away.

But, part of that is accepting that anything else will also flow away with time. That's the part of it all that is hard, but makes it work as a way of getting through life. You start appreciating the good more when it's there, it becomes more real, more memorable because instead of clinging to it, or dreading its loss, it becomes a sort of timeless experience.

The only truly eternal thing is change, so you accept change.

Believe it or not, once you internalize all of that, the bad things in life start to have their own beauty. I'm not saying they become pleasant; being stuck in traffic or having a limb amputated still suck hard. What happens is that such things become just a minor part of life. The threshold for where things go from unpleasant to traumatic shifts.

You learn to accept grief, in particular, and doing so helps reduce the suffering of it. You've lost something, probably something very important. But because you aren't clinging to it, and let yourself really grieve fully, without trying to escape it or numb it, it becomes a form of grace.

Enlightenment is a different thing, tbh. That's more about the spiritual side of things, and I don't really hold on to that part. It's window dressing for me.

This isn't to say that you reach some magic place, btw. As long as you're connected to life, there will be the reality that we are products of hormones and that's all processed by a few pounds of electrified cells in our skulls. Traumas can happen, no matter how you look at them. You're going to have "suffering" in the sense that the concept is used in Buddhism, no matter what. It's a process, a way of moving through life, not a transformation into an internally isolated being that never feels.

Also, "suffering" within the Buddhist concept isn't exactly the best word. It implies that the problems of life have to be major for it to relate. This isn't the case; it really can be about the minor stresses too. Being stuck in traffic is stressful, it causes dissonance and pain. But, when viewed as impermanent, and lived, that stress is reduced and smoothed out. You accept it and just keep going without eating a hole in your gut.