Final Fantasy Hacktics

I'm hoping someone can help me understand the flow of editing these two side by side(attack.out & events to match). I want to have an opening scene, followed by a series of battles with the chance to save between. I also need to know if I'd be able to "restart" the chain from the last map.

I'm hoping to keep the scenes as simple as possible so I can get the basics down. Would it be possible to go back after and modify them? I have a metric ton of questions so if anyone is willing to deal with that and help me please let me know.

Just started using this program as I've just now found out about hacking tactics period... I know. Under a rock!

Anyway, my one major first question is this, I want to make a skill that damages and lowers a stat. Like a knight's power break with standard damage added. I want to know if it's possible to do this given the formulas, or more importantly, other than ASM hacks is there a way to introduce new formulas or modify current ones? Hope that's not a completely ridiculous question... I'm not on the trolley! I got excited today cause I renamed "guts" to "grapple"...