Project Proposal advice and help

Hello everyone, I'm new to this so please forgive my errors and misuse of terminologies and such. I'm uni student tasked with writing a project proposal, and the application is similar to how instagram and snapchat works where you can post pictures online and share them with everyone who's friends with you, make comments, send messages and junk. However I have to use AI to recognize the faces, the code must be open source, I must use datasets that are free with no need for licenses, the application must be deployed and hosted for free.

The problem is that I've never done any of this, I've never had to train an AI model or draw system diagrams or think about SDLC (I've studied it but never applied it), I've never worked with a cloud service (or provider? idk), I've only ever worked and been tested in making Java programs, simple HTML CSS JS websites, APIs using php and using web servers/hosts and made databases in only mySQL. I've also experience with Python, like writing silly scripts using APIs and such.

The only advice I was given that for my front end I can use angular or react, for back python would be a good choice and for a database I should consider PostgreSQL and Firebase for storing photos, but as you can imagine I don't know where to start and they only gave me less than a week to complete it and I'm panicking.

How do I write a good description of the project along with how I plan on using software development methodologies like Agile to do it, I'm guessing for my tech stack I'll be using Python, Angular, Firebase, and Postgres but I don't know how to use a cloud service without getting charged a lot because I'm broke as hell.