google stage A and stage B freediver manual by apnea international, they are available for download unlike AIDA2 and AIDA3 manuals.
that will be a good starting point, then watch videos posted by freediver's channels, like Ian Donalds (freedive UK), Adam Freediver, Freediver Youbuur.
Thank you very much for the advice! I actually have Adam Stern on my youtube, and i have watched a couple vids. Just feel like i need to practice it right after i see it