[Battle] Custom trainer battles not working

Hello there!
English isn't my first language but I'm trying my very best.
I'm very new to rom hacking and currently working on my first hack ever (for fire red) and wanted to create my first custom trainer battle. Up until this point I've managed to fix every problem on my own or with the help of tutorials. But I could only find one other person with the same problem that I have and that problem didn't get solved.
My problem is that the NPC which I created doesn't say what I want him to say but instead says something of which I think, that it should be said by the rival. After that the dialogue is over and the battle doesn't start. The NPC also detects me the moment I walk into his field of view and not after I finished moving. Sometimes after I change something, nothing happens at all except for the NPC saying gibberish. The "trainer" variable in advance map is set to 1.
Is this a common problem?
I hope someone can help me.

Here is my code:

#dynamic 0x800000

#org @start
trainerbattle 0x0 0x001 0x0 @introText @winText
msgbox @afterwards 0x6
release
end

#org @afterwards
= You are too strong.

#org @winText
= Damnit!

#org @introText
= This is our forest!

On Advance map, on the events tab, there is a field box above the offset box called 'Trainer' that says '$0000'. Try changing this to '$0001'

I recommend following this tutorial: https://www.youtube.com/watch?v=8iEV_PRW_-g

In general, follow all these tutorials. They will solve a lot of questions you'll have about romhacking.