To really grasp the fundamentals behind spacetime, it is necessary to undergo a renovation of one's view of reality. Relativity is built upon the notion of something called spacetime. Spacetime is the combination of the four distinct pieces of information necessary to pinpoint an event.
If you needed to give directions to someone, you need to supply them with four key pieces of information. If you wish them to meet you in a building, you may start by giving them the cross streets, say 2nd Avenue and 5th street. The third piece of information might be the floor of the building. Finally, they need a time. These four pieces of information can also be considered height, width, depth, and time.
That much alone should be fairly standard, as everyone is used to dealing with locations as such. However, the change of perception occurs when one realizes that all four pieces of information are in fact intertwined. As a matter of fact, an objects velocity through any one dimension affects its velocity through the other three. Time is not a disperate measurement, it is as critical as the other three coordinates.
The following diagrams indicate how to construct the 4 dimensions, starting from a 0-dimensional point.