confused on how to organize screws

i watch all these videos on youtubers fixing phones and organizing their screws on a magnetic pad and i have asked this question before and one person said they just organize their screws on ifixit guides step by step but like for example if i need to unscrew some mother board screws the ones that hold the mother board in place they’re to many of them and i dont really know how i organize them and also what if im un screwing a screw that is in a another screw what do i do then thanks.