I think you are mixing together Void and Trance. You could do both together like you have been doing, but you do not need to. You could do void without trance. But it could be a helpful thing to do them together.
For void, I think of it like just calmly watching your senses. Just sit there, relax, and you will observe your senses. See what is in front of you, hear all the sounds. But without thinking about them. Just calmly watching. It is hard at first, it does take practice, but you can do it.
For void and trance at the same time, maybe you could sit at a table or a desk, and lean your head onto your arms. Then you will not fall, because your head is already supported.