hi at this moment I am very confused! because.......different between the words " of and for " which place can i use this prepositions. please explain how about these .then I want some example with meaning

Hi, both the prepositions have various meanings. Let's look at the basic meaning of both the prepositions. We use 'for' when we talk about doing something for someone. E.g. - I got this book 'for' you. - You must do something 'for' the society. We use 'of' to denote that something is a part of another thing. E.g. - I ate half of the apple pie. Other examples could be - I am very fond of her. I think of you, etc. etc.