I know they did a lot of hardwork and stuff like that but i just want to know what exactly process did they went through(books,how did they practice,etc),is there any biography on them?cause I just did 7months of tactics(~5000),4months of books(strategy),was able to beat the 1800,2000 elo bots on chess.com 6.5/10 times but lost to a 1500 bot(antonio) due to a blunder.
The Polgar sisters: Training or Genius? by Cathy Forbes states that the main studying was the flash card method. (Chess: 5334 Problems, Combinations and Games by (the father)Laszlo Polgar [https://b-ok.cc/book/857033/54e4d4] provides the puzzles on the flashcards.)
The most important passage (IMO) is the Judith would continue using the flash cards on her free time. When told that she could leave the cards alone, she replied that that cards wouldn't leave her alone. The desire to improve is the most important factor in improvement.