Hi JaiKotia,
Here are the developer docs that explain how to start contributing (start with the readme). The project idea itself is relatively straightforward, we want to update all of the p5.js library, currently written in ES5, to ES6. Here is one article that summarizes the difference between ES5 and ES6 and an overview of ES6 features. We don’t assign mentors until after projects are selected, so for now, it’s best to discuss your project questions with the community at large.