Load Cell output to Kilonewtons

Hello and have a nice month,
I want to calculate the output from a Load Cell ( in Volts after the amplifier ) in Kilonewton.
The sensitivity of Load cell is 2mV/V and the excitation voltage is ± 15 Volt .
And max capacity 200 Kilonewton.
What I have to do, to convert the Volts → Kilonewtons ?

get two points for the straight line:

Read voltage (or just raw value) at zero load. Read voltage (or just raw value) when a known load is present. These two reading will provide the equation for the line (y=ax+b)