How does the Install Port appear when a girl becomes a Reyvateil? So 3rd Generation Reyvateils are originally born as humans but if their mother was a Reyvateil they may develop into one later in life.

From my understanding all Reyvateil have an install port surrounded by a tattoo and since Gathnode Crystals and Life Extending Agents are Physical Objects that get inserted into a Reyvateil with both being somewhat painful this would make it into a hole right?

But i can't imagine how this hole appears. does the skin just open up one day? does a Reyvateil have to go under some procedure to have it made (ie. when they get their first Life Extending Agent) or is it a gradual process?
From the data the Exa_Pico Wikia gathered form the agmes and the Toukoushpere (a segment where characters answered questions sent from users), it seems to be concluded that, after a server mistakenly recognizes a 3rd generation human as a Reyvateil, it begins a long process of correcting what it sees as a somehow ignored Reyvateil that ended up with irregular development, and starts using this human's memories ands senses to develop a soulspace.
The process of developing this soulspace takes about ten days, in which the human enters a comatose state. At the end of the process, the human will have awakened as a Reyvateil, with a Install Port appearing in their body.
So, the Insatll Port appears automatically, after a girl awakens as a Reyvateil.
Unfortunatley, it is not clear of the Install Port is a hole, but from the way it is depicted, the symbol may work as a kind of portal for specific materials (data crystals).