Project: Password Manager

For my software engineering class, I am thinking of building a password manager.

So, my question is what are things, I need to learn before building a password manager also, I never worked on a security tool. The only thing I know is about hashing and salting password. I am thinking of building it in c++(qt), java(suggestion needed) or javascript(nextjs).

Any type of suggestion would be helpful.

cybersecurity manager password password manager project