How to get started with Joplin contribution

Hi everyone, I am a third student of Computer Science and want to contribute to Joplin in GSoC '21 . As far as the tech stack is concerned i am familiar with web technologies like react. I have not contributed to any open source project but i am thinking to do so starting with Joplin. So, any ideas how to started with contributing to Joplin and also with GSoC in mind?
And is it too late to start contributing to joplin to be able to get selected into GSoC '21?