These three aspects are three divisions of time that we are consciously aware of. We can remember past events and thoughts, but we understand that while we are remembering them, they are not happening again. We can think of what the future might be like, but we understand that our thoughts are occurring in the present, and that which we have thought has not yet happened. It is imperative to understand that God did not create the past, present, and future. God only created time.
Time is a one-way flow, untouchable, and unalterable.
The past and the future do not exist, i.e. they are not objectively real. The past did exist, and the future will exist, but all that does exist is the present. The past can be considered reality in that it truly existed at one point in time, but it is no longer real in the sense that it cannot be accessed in our world. We only have access to the present. Likewise the future can be considered reality because it will truly exist, but is not yet real in the sense that it cannot be accessed.