they said to metamorph a monster from the area of thamasa but i dont know how to meta morph...

Meta Morph??? I have no idea.... Unless you mean Tira (or whatever the nintendo made her default name) transforming into a Esper... Then thats right after you get to zozo the first time and get you first few esper in the game!!

use the esper rangnarok (sp?) his attack is matamorph. if you need anything more just ask.

what does terra's morphing do because it only lasts afew seconds before she changes back and if you can get a hit off in those seconds it seems to be normal damage anyways

plus you can only morph like once every couple battles???

longer you gain exp without using terras morph for the longer it lasts. So if you play the whole game without using it basically by the final fight with kefka it's pretty long lasting. Although I don't even use her in my fight with kefka so I just go through the entire game without using it.