Master! How to solve the above problems

Help experts! How to solve the following problems? I want to create a PHP for file upload/download management. the requirements are as follows: I cannot use a database, set several usernames and passwords, set an administrator account, and ordinary users can manage their own files, the administrator can manage all files. I am a newbie. I can find the code reference for file upload, but I don't know how to do the above requirements. I hope you can ask for help! How to solve the following problems?
I want to create a PHP for file upload/download management. the requirements are as follows:

You cannot use a database. you can set several usernames and passwords. you need to set up an administrator account. common users can manage their own files, and administrators can manage all files.

I am a newbie. I can find the code reference for file upload, but I don't know how to do the above requirements. I hope you can consult with me. of course, the more detailed the better!

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Train of Thought. Create a txt file by yourself to store the initial administrator. Then, perform operations on the document.
What do you mean by file management? It makes no sense to simply create and modify
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1. files can be used without databases, not the main
2. if a file is recorded, the operation Reliability decreases when a file is modified (for example, a file is deleted. This should be fully taken into account
3. one user can have a directory and each user can operate in the directory of each user
4. the user name and password can be directly written in the program.
5. a brief description of the downloaded file should be provided.
6. instructions can be saved in a centralized manner or together with the downloaded file

After thinking about this, you should confirm your plan first and then talk about it again.
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Check the directory name.
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Enable ftp server