The dimensions are labeled on the right of this graphic and correspond to vast regions (the blue circles in the background). These regions are within us and around us.
Hod and Netzach correspond to the fifth dimension, which is where we experience dreams.
However, all of the dimensions are here and now, interpenetrating each other, we simply lack the ability to perceive them directly. We can perceive something of Hod though: our emotions are "echoes" of Hod, while our thoughts are "echoes" of Netzach. Those who awaken consciousness will eventually see those regions directly, as easily as we see through our physical eyes.
Between the third dimension (Malkuth, the body) and the fifth (Hod, Nezach) lies the fourth dimension: vital energy, the body of chi. It is the conduit between them.