Final Fantasy Hacktics

Hi, I want to find a way to edit random battle to change enemies that can appear, number of allies I can use. The iso I want to edit is an already patched one, I just want to change something. There is a tutorial for this? I'm complete new of FFT modding.

For the ennemies on field FFTPatcher is what you need. (Tools section)
For the squad size, You will need this : https://ffhacktics.com/smf/index.php?topic=9749.0

Not sure there's a tuto. But it's quite intuitive. You'll have to try and see what happens.