[Freesurfer] New User - Gyrification Index question

Hello, I am a new user of the freesurfer platform. I am a high school junior conducting research on brain MRI scans and came across this wonderful platform. However I am not very sure how to proceed with my research - I am trying to find the whole brain Gyrification Index, which I did manually on a different software called ImageJ using multiple image scans of brain slices. Will freesurfer be able to analyze brain scan images and provide a whole brain GI or does it only analyse and provide local GI which is what I found through some forums? If so, are there any tutorials to learn how to do that? Do I need any other software like MatLab to find out the Gyrification Index?

Thank you in advance! Ankita