I can give an example to explain the falling of hair after a hair transplantation.
Imagine a plant that bears fruit. When a plant is first planted, it first needs to root and then give fruits. The same goes for the hair.
Hair follicles are like veins in a plant. Our hair starts producing hair when it feels ready, after constructing the vein structure in the hair follicles – just like in plants. That means the hair starts growing 2-3 months after the hair transplant. The hair totally grows after the 7 and 8 months.