When you type "A" on a standard keyboard, the computer sees the code for "A". In a legacy font like Shree-Guj-0768, that code is visually remapped to look like a specific Gujarati letter (e.g., "અ"). However, the underlying data remains English. This is why opening a file typed in Shree-Guj-0768 on a computer without that specific font installed results in random English characters appearing instead of Gujarati text.
We recommend printing the official Shree-Lipi layout card available on their website.
Often follow a phonetic pattern (e.g., 'k' for ક, 'g' for ગ) or a traditional typewriter layout like "Bakaman" (બકમાન).