Conversion Equation using Generalized estimating equations in SPSS

Hello, I got two devices that measure same group of people. I would like to create a conversion equation to translate the measurement from device A to device B using repeated-measures models with generalized estimating equations. May I kindly ask how it actually works in SPSS (e.g. which variable should i put in each column in SPSS)? Also, may I ask if I would like to validate the equation, which statistical analysis shall I use? Thank you very much.