First, Merry Christmas.
Perspective is nearly always a consideration of assessing the past.
Viewing the past in the 'now' is not a choice.
The 'now' requires events to pass before they can be assessed.
To view events in actual 'real-time' would require the ability to observe AND process events as they are happening.
This might seem like what we do but in actuality, the real-time events we observe and process are already established events.
The light we see from a light bulb turning on has already happened by the time we see the light.
The light from the Sun has already erupted from the Sun about 7 minutes before we see it.
The issues is not the amount of light but the time delay between initiation and reception and processing.
In the case of the light from the Sun, there are many things that can occur between the time it leaves the Sun and it reaches our eyes and is processed as light by our brains.
In the reference of a light bulb, the duration is shorter but there is still duration.
That duration establishes the past.

This understanding is important because relative to our own perception we might think we exist in real-time but in actuality we always exist in the past.
Now, consider that if everything we experience is the past and that past is a series of snapshots of time, focusing on a single snapshot could establish a destination for time travel.
The problem with time travel is that we might be able to focus on past events from recorded history, we do not have enough data to focus on the precise moment of occurrence of any event.
The Universe has changed from that 'state'.

Not only must the time device calculate the exact moment of the observable state, it must calculate the exact state of all unobserved states that existed in that moment in the entire Universe. So, even tho you might focus the destination on a single event in a given life, if the Universe is not aligned with the events that transpired during that specific event, you have no stable destination.

From a different perspective, To accurately describe events that happened during a significant event, all the parameters must be considered for that specific time according to the present state of the Universe at that specific time.

This all lends to the idea that the perception of the individual dictates the reality that actually happens. If the event happens before the assessment (which it does) the event is locked to the conditions that were occurring at the actual time of the event, not the perceived time of the event.

Take Messier 87.
The events we perceive happening at Messier 87 are actually events that happened 52.49 Million Years ago.
The light that we see in real-time now, happened at Messier 87 52.49 Million years ago. We are only just now seeing it as a reality.

That same light speed limit applies to all light.
So when you are in the dark and turn on the light switch to light the lamp for your room, that light striking your eye and being processed by your brain has already happened by the time you understand it as light.
You can probably calculate the duration of time it takes but the significance to this thread original topic (OP) is that duration has occurred and what we see as real-time is the past.

Since human existence is locked to the past, the only thing any person can consider is the past.
We exist in the past.
If we could experience the presence, as actual now, we may have a different take on reality.

Once you can accept this, it is easy to understand how we understand time.
The past has already happened, the present is happening now but is only perceived after the fact and the future is a projection of present events that could occur based on our own perception and evaluation of the past which we experience.
The future is dependent on the past.

All this is fundamental to me.
Its as real as the electromotive force that makes objects 'feel' solid.
The atoms in the keyboard in which I am typing this have a force that allow me to punch the keys in such a sequence that they make sense.
Those keypunches are happening in the past, as I type.
I press the "M" key and time happens from the time I pushed the "M" key and the time it is displayed on the monitor. By the time the "M" shows up, time has passed.

As an application to science fiction, this can be significant in some ways.
The details of time travel destinations, the understanding of reality of the characters and much more.
A character that can assess real-time events will have an edge over those locked to the past.
How much can you get accomplished in the duration of a light bulb lighting a room?
At our present abilities, none. Thing is, in science fiction, we can violate that delay.
Science fiction is not locked to existing in the past.
Science fiction allows us to violate time.

When we observe and process the light from Messier 87 we have time to make many things occur during the 52.49 Million years since that light left Messier 87.
Well, its the same with the Sun at about 7 minutes and the light bulb that "seems' instantaneous.
Imagine what you could do with a millisecond of time.

Even if you place the light bulb against the eye, its journey requires duration for it to have significance.
It must register on the photo receptor of the eyeball, that signal has to journey the optic nerve, that information must stimulate axons and dendrites to establish memory. That memory must be processed by the brain as light and transmit that significance to our higher brain functions so we can understand it as a light being turned on.
All of that takes time.
We may understand it as real-time but it really isn't.

Playing with my camera