It's time to nudge everyone towards their Focus! Thanks to version M20, p565-600 is a lot to take in, so let me simplify, and also explain to everyone where your PCs are at this point.
Focus = paradigm + practice + instruments.
Your paradigm is your belief or understanding of how magic works. Eg do you think magic is all about faith, or all about illusion over reality, or about power to make things happen, or about cause and effect, etc.
Your practice is what method you (think you) use to make magic happen. Eg, does your magic work like alchemy, or witchcraft, or weird science, or miracles, or personal spirituality, etc
Your instruments are the tools you use to do magic. Eg, do you use wands, gems, books, bones, symbols, music, numbers, sex, drugs, dance, etc
So far, because your PCs are literally experiencing magic for the first time, I've ruled that it's flexible and spontaneous, kind of 'so long as you can think it, it happens'. That's how they discover they are magically inclined or awakened.
But what will happen next is that, more and more, if they seek to reproduce the same ability, they need to resort to whatever they were doing previously in order to bring about that effect. Eg Eldarin has been describing how Wren turns to musical pattern as a means of bringing about a magical effect. To go further, she'll need to use an instrument to replay the same tune, or different tunes. Another eg, Psybermagi has been describing Kyle as using his phone to produce certain effects. He'll need more apps, or perhaps different processing power, to cast more things. KCC had Minsoo sing certain lines of songs, etc.
So in general, we're heading in the right direction. Those of us who have yet to flesh out these aspects, you can start sprinkling them in. I'll let you know when I'll start to invoke the rules (such as greater difficulty to cast magic without a focus).