This is my first time playing this and now I'm at the point in the game where I'm in the North Cave fighting sephirohp, I lost to him quickly and I need suggestions, I've just only discovered the barrier materias since, I was too stingy to buy them back then. Can any of you help me and that Jenova thing before Sephiroph how do you beat it quickly, I'm talking about the one where you use 2 parties to fight.

I've also found Ultima Weapon, when I fight it it just keeps running away, what's the solution to this?