Hi Hugo, welcome! I saw your other thread, glad you've come to join us!
You need this book:
https://www.amazon.co.uk/dp/B016USSX5O/ref=dp-kindle-redirect?_encoding=UTF8&btkr=1
Read the opening posts of this thread and thread 7. The diet itself is a low carb high fat plan- you can eat meats, cheese, nuts, full fat dairy, most veg (no potato, and limit other sweet veg or veg that grows underground), and try and avoid rice, pasta, grains such as wheat and cous cous etc and sugar. To really rapidly reverse T2 and Pre-diabetes, you can stick to a calorie count of 800 a day. Not all of us do this, and certainly not every day, so there's no pressure to reduce your calories rapidly straight away. You could download a tracking app such as MFP (I use the delightfully named 'fat secret' !)
I really felt for you reading your post. Please use this board to ask any questions and just to chat- there's quite a big community of us on here, some have been here for ages, some are new, but we all understand where you are because we've been there, or similar.
Good luck 