Thanks for the ping, @ecebayram !
@blin, have you had a chance to see the SAA overview video that @jodiefm put together? There is a thread on it here: SAA data in PPMI - data overview video .
My understanding is that it largely covers what is in the PPMI Data User Guide section on SAA (begins on page 32).
There are also additional PPMI-related guidance documents which live here in case they are useful: https://www.ppmi-info.org/access-data-specimens/guidance-resources.
Let me know if the video/user guide aren’t able to clarify and we can investigate further!