Hi, My name is Hasnain. I've read and understood the project specifications, I'm assuming that you have an up and running cloud storage web app (Firebase?) and you're stuck with authentication and stuff. I might be able to fix this for you.
As for my technical background, I've over 3 years of web development experience. I'm currently working as a software engineer in a Swedish company here in Pakistan. I mostly use Python and PHP for my web development projects. I'd love to get more details from you about the project, send me a message.