First you'll need to learn how to use a spreadsheet. I use the Microsoft Works Spreadsheet that came with my PC. There are more sophisticated spreadsheets but this one is all you'll need. You can arrange the details to what works best for you. Use the instructions provided with the program to learn how it works. It will be worth the effort.
I set mine up by columns for chapter, page, characters and action. I use just enough detail to jog my memory.
If I want to change the order of the plot's action I can easily find the details.
If I want to add a chapter between the chapters I've written I just add a row.
If I want to make a change I can instantly find what chapter and page it's on.
Of course with each change you make you must adjust the details of the spreadsheet (like page numbers, action, etc.)
I hope you'll find this useful.
Note: For the details from my novel I have a copyright registration on file with the U.S. Copyright Office.
You can use the spreadsheet idea for your own work.