The disk floats approximately three feet above the ground at all times and remains level. It floats along horizontally within spell range and will accompany you at a rate of no more than your normal speed each round. If not otherwise directed, it maintains a constant interval of five feet between itself and you.
The directing part only has to do with the fact that you can control the distance that it follows you.

So:
  1. It can only follow you.
  2. The default distance that it follows behind you is 5'
  3. You can direct it to follow you at an interval closer than that.
  4. You can sit on it and float, but it won't move.