Why in the world would I tell you to step away? Both of these sound awesome! ;D
With respect to describing a magic battle from Matt's POV, I think that there are a whole lot of possibilities for describing it. Most of the time in shows and such, spells take the form of projectiles that make sound effects, so you could easily describe the sounds that the spells make as they fly. (Also, of course, the sounds that they make when they land!) If the magic users have distinctive voices and the magic requires an incantation, then that could be another way for Matt to follow the action. If they have very different types of powers (i.e. one uses fire and the other uses lightning), Matt could probably differentiate between them by smell, too (fire=smoke, lightning=ozone), but after a while, the smells would probably blend together so much that they wouldn't be too helpful. He could also potentially taste the same sorts of things that he's smelling. Finally, it could be very interesting to try to find ways for Matt to try to describe the feel of something fantastical moving through the air: how it affects the air around it without seeming to obey the laws of physics, maybe displacing a different amount of air than he would anticipate. It could be really disorienting for him, which would also be fun to try to capture. There are lots of ways that you could describe Matt perceiving the magic battle, and the fact that he would probably be utterly bewildered just means that if it doesn't come through perfectly clear, it would make sense from an audience member's perspective that it's Matt's confusion, not the narrative's.
When you need to have a character thinking for a while, it might be helpful to try to think of what the audience needs to know about the character's thoughts. You said that Foggy wakes up and tries to figure out what's going on, so that probably means that you'll need to establish 1) where he is 2) where he was before he got where he is and 3) how he thinks he might have gotten from there to here. Other details (such as his physical state, the appearance of the room) could also be useful to know. The ultimate purpose of narration is to impart necessary information to the audience, not to simulate a person's actual stream of consciousness (unless stream-of-consciousness is what you're going for, in which case it'll be up to the reader to put together why Foggy's thinking what he's thinking in the way he's thinking it). If you find action easier to write, then think about the mental space as an action scene. What does Foggy need to notice to make the decision/draw the conclusion that you need him to? How much does the audience need to know to effectively understand the scene? Once you figure out those answers, you will just need to put them in an order that makes sense to you (just like in an action scene) and describe them. Keeping your narration down to only what is necessary and/or interesting should let you create a narrative that will be engaging.
Re: Help!
With respect to describing a magic battle from Matt's POV, I think that there are a whole lot of possibilities for describing it. Most of the time in shows and such, spells take the form of projectiles that make sound effects, so you could easily describe the sounds that the spells make as they fly. (Also, of course, the sounds that they make when they land!) If the magic users have distinctive voices and the magic requires an incantation, then that could be another way for Matt to follow the action. If they have very different types of powers (i.e. one uses fire and the other uses lightning), Matt could probably differentiate between them by smell, too (fire=smoke, lightning=ozone), but after a while, the smells would probably blend together so much that they wouldn't be too helpful. He could also potentially taste the same sorts of things that he's smelling. Finally, it could be very interesting to try to find ways for Matt to try to describe the feel of something fantastical moving through the air: how it affects the air around it without seeming to obey the laws of physics, maybe displacing a different amount of air than he would anticipate. It could be really disorienting for him, which would also be fun to try to capture. There are lots of ways that you could describe Matt perceiving the magic battle, and the fact that he would probably be utterly bewildered just means that if it doesn't come through perfectly clear, it would make sense from an audience member's perspective that it's Matt's confusion, not the narrative's.
When you need to have a character thinking for a while, it might be helpful to try to think of what the audience needs to know about the character's thoughts. You said that Foggy wakes up and tries to figure out what's going on, so that probably means that you'll need to establish 1) where he is 2) where he was before he got where he is and 3) how he thinks he might have gotten from there to here. Other details (such as his physical state, the appearance of the room) could also be useful to know. The ultimate purpose of narration is to impart necessary information to the audience, not to simulate a person's actual stream of consciousness (unless stream-of-consciousness is what you're going for, in which case it'll be up to the reader to put together why Foggy's thinking what he's thinking in the way he's thinking it). If you find action easier to write, then think about the mental space as an action scene. What does Foggy need to notice to make the decision/draw the conclusion that you need him to? How much does the audience need to know to effectively understand the scene? Once you figure out those answers, you will just need to put them in an order that makes sense to you (just like in an action scene) and describe them. Keeping your narration down to only what is necessary and/or interesting should let you create a narrative that will be engaging.
Hope this helps!