Nhờ sửa bài giúp

i'd like ask in short text about how ,where use "present simple ".I don't understand how is difference between sentence " I live in Poland" and " I am living in Poland". here and here is similar. how is difference . other example "I eat bread" and "I am eating bread" , " I read book" and " I am reading book" , " I have two sons" and " I am having two sons" and a lot of other. i know that build is similar verbs , subject and rest sentence.

I know that form with end "-ing" is use in "present continous." please explain these examples whether it's basic rule grammar or is logical explain