hey..
i understand what you mean, but it's complecated, cause arabic letters are not like english letters. See, when you write in arabic letters are combined, and usually some changes happen to change the form of a letter. For example, the أ letter is written the same at the beginning of a word. but it changes at the middle of it to this form ـأ .Another example: حـ becomes ــحــ.
Therefor, you should start teaching arabic letters Individually to children.
And you can teach them letters indevidually at there three shapes: at the beginning of a word, at the middle and at the end.
i am wondering if you are an arabic native speaker?
becouse you might notfind this relevant.