Time is merely the product of our minds. Imagine a group of children who had been raised in a hermetically isolated situation without any language for time. They found a huge pendulum hung in their house, and every morning they started it swinging. The word time would not enter their language, and time had no reality apart from their habit of counting pendulum swings.
Dimensions are merely directions of movement which can be measured .
We can measure laterally and vertically to yield the three dimension of space. Then we add sundials, the counting of pendulum swings, nights and days, phases of the moon and the annual movements of the sun. As we translate every use of the word time into measurements on a sundial, counting swings of the pendulum, rotations of the earth, phases of the moon, etc. it soon becomes obvious that time has no reality apart from the construction of our minds. So when we say God is outside time it can only mean that God does not count and measure in those ways. Nor does it make sense to talk about time going backwards.