This does not mean "at this moment," but is used to draw attention to the important point that follows.
# according to the law
"as God requires in the law"
# a copy and shadow
These words have similar meanings to emphasize that the tabernacle was merely an image of the real tabernacle in heaven. AT: "a vague image" (See: [[rc://en/ta/man/translate/figs-doublet]])
# shadow of the heavenly things
The author speaks of the earthly temple, which is a copy of the heavenly temple, as if it were a shadow. (See: [[rc://en/ta/man/translate/figs-metaphor]])
# It is just as Moses was warned by God when he was
This can be stated in active form. AT: "It is just as God warned Moses when Moses was" (See: [[rc://en/ta/man/translate/figs-activepassive]])
# was about to construct the tabernacle
Moses did not construct the tabernacle himself. He ordered the people to construct it. AT: "was about to command the people to construct the tabernacle" (See: [[rc://en/ta/man/translate/figs-explicit]])