Use a calculator to find the inverse of the orthogonal matrix matrix Q=[ 0 0 1 −1 0 0 0 −1 0 ] and verify Property 1 above.

Is that a 3x3 matrix?

(0 0 1)
(1 -1 0)
(0 -1 0)
has inverse
(0 1 -1)
(0 0 -1)
(1 0 0)
I'll leave you to verify that the product is a 3x3 identity matrix.