Advice for aspiring bowyer

After the lovely YouTube algorithm recommended me some bow making videos with basic materials and I have a few questions

1. How do I make a bow for a target draw weight with no frame of reference? I.e 30lbs vs 50lbs bows and the size for long and short bows
2. What is the best string I could get from a hardware store like Menards? The fellow on the yt vid used Mason line and said paracord stretched too much
3. Arrow weight ratio was never mentioned. I do know that lighter bows need lighter arrows and visa versa, but what is the proper ideal ratio for draw weight vs arrow weight?
4. Any common mistakes I should be aware of before I start?

Thanks in advance for any advice yall could offer and wish me luck on my first bow build!