TLV9002: Single-supply strain gauge bridge amplifier circuit

Hi Team,
I want to design a circuit that measures the readings from a strain gauge.
The Bridge resistance is 350 Ohms.
The excitation voltage is 12V.
I am following this application note as my reference. (https://www.ti.com/lit/an/sboa247/sboa247.pdf?ts=1651680187339&ref_url=https%253A%252F%252Fwww.google.com%252).
The output of the bridge is 2mV/V.
 
My required output voltage is in the range of 0V - 5V
In the application note SBOA247, 
1). The Vcm (common-mode voltage) is taken as 2.15V. Why is that?.
2). How was the Vcm calculated?.