My initial response to this question is to tell you to ask your teacher or whoever has set you this assignment. This is because, at the end of the day, it is your teacher who will be grading this assignment, not I, and they might have different ideas than I do. However, having shared this caveat, let me tell you what I would expect from a symbolism booklet if I had set this assignment.
I would expect to see a booklet with one page or thereabouts focusing on each symbol in this excellent book. So therefore you would have one page focusing on the sea, for example, and another page on the fish itself. Each page would include all the quotes from the text that are relevant to how that object, character or action is established as a symbol, and would conclude with a paragraph analysing the quotes and suggesting what the meaning of that symbol is in the novel.
So, to complete this assignment, you will need to read the book again, noting down all relevant quotes, and then organise your quotes into the separate symbols and then use one page per symbol. Hope this helps! Good luck!