Regarding Google Summer of Code'18

Sir/Ma'am,
This is in reference to GSOC'18.
First, a little about me:
I am a second year computer science
engineering student from India. I have programming experience of 3 years in
C++ and C.
I have not yet started to contribute to any Free and open source software
till the date. But I'm looking forward to do so.
I've been using LibreOffice open source softwares like writer, impress and
many more for a long time and now I want to contribute towards an open
source project, but before that I'd want to know a few things which are
probably not mentioned in Libre's wiki page and other links since I want to
enter GSOC'18 and also to make real use  of my programming skills. So here
are my queries:
1.As far as I know, there are various ways in which a user can contribute
to FOSS. One being bug finding, another being providing working codes,
suggestion for enhancements, etc.
In order to get into GSOC, which type of contribution should I make more?
2. How many projects should I contribute to to get selected in GSOC?
3. If I make contributions to a project and it gets pulled into master, who
would know that I did it? I mean will there be any proof of my successful
contributions so that I can add it to my CV or something like that.
4. What is the magnitude of projects that I have to contribute? One, two,
three or more?
5. Do I need to create a project on behalf of LibreOffice before I apply
for the program? Or do I have to do it alone..
-

That's all I had in mind. I apologize if I've asked a query whose answer is
already mentioned on your website..
I hope you answer to the queries; really important for career :-)
Thanks!