I want to fully understand Godel's incompleteness theorem.
my background knowledge are these: analysis1, linear algebra1,2 , abstract algebra1, topology1
and I studied logic by myself while reading this book 'introduction to logic, Irving Copi'
I also read the book 'Gödel's Proof Book by Ernest Nagel and James R. Newman'
but I think this book is not good enough and it has some errors
I wish I could read the original Godel's paper but I think there are some prerequisites which I should learn.
so what steps do I have to take to fully understand godel's theorem?
I think it would be good to recommend books to read in order.
I'd second @Lereau's recommendation of An introduction to Gödel's theorems by Peter Smith. What a surprise!
You can download a PDF from https://www.logicmatters.net/igt (though the pbk is very cheap, if like many people you prefer to work from a physical book).
But you can also find other recommendations -- with descriptions of how they approach the topic -- in Chapter 8 of the Beginning Mathematical Logic Study Guide which you can download from https://www.logicmatters.net/tyl.