Worms doesn't know, that's why he sent you to a website. Spacetime is
a fictional place invented as a math construct so that we can calculate
the motion of objects through time.

According to Einsein, every object has a so-called "world line" which
indicates the object's past, current, and future position wrt its
motion through the universe.

AE invented a universe having the same exact dimensions which our own
universe contains, i.e., length, width, depth, and time. He did it to
show that he was not talking about our universe but an imaginary one.
His lemmings, however, insist he was talking about a real place and
they talk about it as if it exists. Go figure.