I'm so confused, did I miss something because I don't rememeber Cassian teaching Sienn how...

Same. Must have been the previous chapter since much of it was cut

Chapter 62 page 5!! It was not explained in detail but Sion was trying hard to use his holy powers with Cassian instructions and Parvel was laughing that it doesn't work, but when the light started appearing Parvel hid it with his hands and Cassian let it go

Thanks!

omg you're right thanks was thinking of reading it all over from the start and this was proof

Honestly rereading is a good idea with this story
I though of rereadngg it too, because with weekly updates I forgot a bit of continuity of the story