hi guys is there any guide to learn the way of datafiles?!

There isn't much to it... Read the references.

After that, ask specific questions.

Something I've concluded after some time here is that you won't find a full documentation explaining everything in detail. You're better off if you only go learn something if you need it.

For example... I don't know how to modify config files because I only need to read them.

Something else... If you really go do this I suggested, you'll learn how to use datafiles, but something what is not mentioned in the docs (I didn't see it there) is tht if you, in the configuration file, says that all packages can read/write files, that'll allow scripts outside packages do the same. So, "all packags" actually means "all packages and everything outside packages".

Anyway, go read the references. I don't know anyway around this.

ok i won but i dont undestand something...
now i'm able to read and write datafile in game but i dont understood when it saves on a datafile.txt under /data/ds/pkg/ folder???

Yes that is where it saves datafiles. I wouldn't worry about how and where POL saves them, just that they are saved and accessible within the game. Datafiles get saved when there is a worldsave just like the rest of the data.

I've realized just now... I've got his question wrong.

I'm sorry dude. I was talking about files (file.em) and not datafiles (datafile.em). Just ignore what I said.