Welcome to the Plone community, @shivamluthra and @bringtree. We are glad you are interested in working with us for your GSoC. For both of you, the best way to get started is to download and explore Plone (linked at the top of this post), read the documentation on how it works, and how to work with it (also linked above), and explore the ideas in our ideas page. If you want to get a start on understanding Plone better, you can find a link at the top to some issues in GitHub that we've marked as appropriate for beginners. There is also good documentation linked above on how to contribute.
As you develop specific questions, please feel free to ask them in posts to this forum. If they are related to any of the ideas in our list, you can @-mention any of the mentors here and they will see your messages. Do keep in mind that we are mostly working folk and it may take a short while for us to respond to your questions.
Thanks so much for looking into working with Plone. We look forward to seeing your proposal rough drafts starting March 20.