mission help

I dont know if this is the right place for this but im stuck in the aurora glade mission because i cant figure out whjat udo to attune the thorn peestal. could anyone tell me what to do?

talk to the spirit/ghost, a crystal should appear, take that and put it in the slot of the other pedistal.

The last part(or almost last) you have to attune every portal to your side before the white mantle does it.