Yeah, I had a lot of trouble.
Spoiler It looked to me like you use Flames to reset. Then Frostbite in a timed dose to move the beams to the right position. Too much or too little frost? Might as well reset with heat and start over. Mostly you have to reset after every cold burst until you get it right. Oh and have a play with the buttons first so you can figure out what it is you want to achieve.
Haha, then that uppity Synod mage accused me of some dastardly plot!!! I think he was right. lol.
I had to ask myself, why didn't the Synod guy do the stuff with fire and frost, save us all that trouble? Maybe he was unskilled in Destruction? Well, I'm not either. I'm an assassin and use blades. lol.