The three fabrications get boiled down to what leads to bodily, verbal, mental kamma on the large scale. Bodily fabrication is the in-and-out breathing. Verbal fabrication is directed thought and evaluation, how you talk to yourself. Mental fabrications are perceptions and feelings.

"There are three kinds of fabrication: bodily, verbal, and mental. On the large scale, that refers to bodily kamma, verbal kamma, and mental kamma as they give results in this lifetime and on into the next. But in the present moment, the three fabrications get boiled down to what leads to bodily, verbal, mental kamma on the large scale, and here the Buddha gives different definitions. Bodily fabrication is the in-and-out breathing. If you weren’t breathing, you couldn’t do anything physically. Verbal fabrication is directed thought and evaluation, how you talk to yourself: You direct your thoughts to a topic and you make comments about it. You may ask questions about it, and when you’ve thought in those ways, that’s when you open your mouth to speak. Finally, mental fabrications are perceptions and feelings: the labels you put on things, the feeling tones you have. These are the building blocks for all mental kamma."

~ Thanissaro Bhikkhu "How to Change" (Meditations11)