I’d recommend looking into Dr Jason Fung. He’s a good introductory resource for fasting. He is a real Dr in Canada (nephrologist) and has a lot of clinical experience. You can look him up on YouTube and he has a few books as well
As far as prep for your upcoming fast, I’d recommend cutting carbs in your diet in the weeks leading up to it
Do OMAD for a few days even a full week. That’s what I been doing to prepare for an extended fast I started 2 hours ago. I’m pretty used to 23 hour fasts now, I’ve tried to fast with no prep before and I failed after 1 day. But if you feel like you can full send it then more power to you bro. Rooting for u regardless. Good luck 🤞🏼