There's a pretty tough Tank switching mechanic in Garuda EX where the tanks really have to know what they're doing. Most of the time my groups have wiped and we weren't able to complete were because of that. For other classes it's not that tough as long as you know the positioning and mechanics. I'd recommend this video if you want to learn those quickly and you're not a Tank. If you are, you'll need to do a bit more reading before you attempt it.