Hi @prasanna5,
Great to hear that you are interested in the projects. Regarding how to get started, I wrote this post last year and it’s pretty much still up-to-date. Implementing Incremental Re-Parsing in SwiftParser, GSoC 2023 - #2 by ahoppen
And yes, as far as I know you can submit two project proposal. If you do have a preference for one of them, I would encourage you to mention that in your proposals as well.