Setting up GIT Repository

Hello,

I am in the process of trying to create a GIT repository and I am struggling to export all the relevant classes from Studio, as I only have access to Studio and not able to export via the Management Portal. Does anyone have any suggestions as to how I can export from Studio as one project to include all the relevant folders and its associated classes?

Are there also any recommended documentations/links you would suggest to help me get a better understanding of  GIT and how it works etc?

Thanks!

Pavi