I can try to give a brief definition of those terms:

The present is the set of simultaneous detections taking place all across the universe, composed of all the events taking place at a given objective "now".

Spacetime is defined by all past emissions related to all present detections through the light speed ratio. It's the network of interactions that connect past and present throughout all past history of the universe at a given time.

Time is not a single concept, there are two types of time: The objective time in which the lightlike interactions that shape the universe develop, and the subjective time, in which every entity defined by a particular set of said interactions conceives its own sense of time flow, by comparing the detections that compose its internal structure with those that make up other external phenomena.

Time dilation only occurs in subjective time, and is nothing more than this comparison between the frequency or length of the interactions that recreate an entity’s structure with respect to other entities or processes it is able to detect. Objective time is not affected in the slightest.