Check this link, translate the page. If help was needed with translation I can help with that.
Also, I managed to find some photos of comparisons table of the Avestaee, Modern Farsi and Modern Arabic (Koofi is the original language).
The first one is a handwritten one.
The second one, on the first row, it is modern Farsi alphabet, the second row is the way it pronounced in Farsi, the third row is the pronunciation of Farsi alphabet in English, the forth row is the actual English equivalent of the Farsi letters.
The third photo is Avestaee and Farsi alphabet.