As a modality, thoughtform manifestation rests upon the notion that our intentions/thoughts create a sort of energetic hologram, which "pings" the Vibrational Web that underpins physical reality, setting into motion a process that eventually gives rise to those intentions/thoughts in tangible physical form.
It all sounds so impossibly abstract, doesn't it? That's because human language is never fully up to the task of describing what happens in the etheric realms. And even if it were, in their usual waking state our minds would still find it very difficult to comprehend.
However, it is possible to see a visual representation of what that process might "look like" if you could "see" it in motion.
Cymatics is the study of how vibrational stimuli shape physical media. Like sound, your thoughts are vibrational in nature, albeit at a level so profoundly subtle we have no way to measure or visualize them except to notice things they give rise to. In the video below by Nigel Stanford, you can see how music/sound vibration affects the behavior of liquids, solids, fire and electrical arcs. Now imagine that the music is your thoughtforms, the air through which it is transmitted is the Vibrational Web, and the patterns that arise in the liquids, solids, etc. are those thoughtforms translated into their respective physical forms.
You see? ~Rishika