The Five Dimensions:
Try to think about the concept of infinity, from infinitely small, to large, to never ending. Try to visualize and imagine each of the five dimensions, starting with the infinitely small point, on up. Try to do this by visualizing simple geometric figures, see them in your minds eye.
After you have practiced with and mastered the simple forms, circle, triangle, square and pentagram, try moving them around at will and view them from all different perspectives. Then go on to the more complex forms shown next, the 6, 7, 8 and 9 sided forms.
Then try to visualize a hypercube, and see it from different angles.
With this visual basis, try to visualize, imagine and feel the interrelatedness of all matter which Science has discovered as a cold fact. Sense and feel how your body, like all matter in the Universe, is in energy interchange with all other bodies in the Universe. Start off with the physical objects immediately around you, and then expand outward in ever larger vistas, to finally include the whole Universe.
Then when you are ready try the Meditation on the Hypercube exercise created by Wilhelmine Keyserling. She is a teacher of Yoga and philosophy in Vienna, Austria who is the author of many books on these subjects and also happens to be Arnold Keyserling's wife.