I don't think that time is as simple someone could imagine. If you look at relativity any observer seems to have its own timeline. There isn't one thing you could globally call "one moment". An space-time event between two things is a point at which they have an interaction at the same moment.
I believe that Einstein stated that past, future and the present exist simultaneously to make it imaginable. While the truth is that it is not. There is no strict order in which moments follow other moments. That concept also gets lost in quantum mechanics as you often don't know when something exactly happened. If there are 2 independent interactions AB and CD it is not important in which order they happened and in relativity the order can depend on the observer. In quantum mechanics the order might not be defined at all.
To give an example ( extreme ) if we would meet and I would travel away to another solar system at light speed and come back at light speed you would see me travel for thousands of years while it would only take one second on my timeline. While I accelerate to go back I see you pass thousands of years.
The best way I found to imagine it is when you look at someone from a distance; if we walk away and look at each other from a distance you would say that I look small and I would say that you look small. According to relativity the opposite happens with time; I will say that your clock runs slow, which means that 1 of your seconds looks big and you will say the same about me. Then if I turn and walk back to you this makes a huge difference; if I turn slightly I will not end up where I was; I will end up somewhere else. How farther away I was when I turned how bigger the change in the position when I arrive back.
According to relativity; if you have speed the clock of the other seems to run slower like the perspective of being farther away. Then when you accelerate you take a "turn in time" with the effect that you cross the timeline much later.
The result is that you can't put a global time label on events. The thing we call time falls apart. In the extreme you could imagine that you meet someone 4 times and that the other thinks it happened in a different order. That doesn't happen in the theory of general relativity; the order in which you interact remains the same but the time between events you experience can be completely different.
This doesn't mean future and past have to exist. It just becomes completely impossible to imagine a scene with different players at different positions and times without that. But physics happens locally ... this scene might just be imagination; an attempt to imagine the impossible. We try to model things with dimensions; you could state that we all have different dimensions and that those dimensions relate to each other following rules which depend on location and speed. My dimensions seem normal and if you have speed relative to me your dimensions seem normal to you but are kind of odd seen from my point of view.