How to start implementing NFS in C?

How to start implementing NFS in C?

As a project, I have to implement a subset of operations of the SUN
Network File System Version 3 in C. Going through RFC's and other material
available online, I have understood some things and confused about some as
well.
To implement RPC's, do I need to use XDR and consequently rpcgen. If I do
so, the whole point of implementing NFS would be defeated because
everything would be automatically generated and then I just need to write
client and server programs.I'm not even clear on how to use XDR in the
first place because I have to implement operations like open,mount,umount
etc.So, the client side file system needs to call LOOKUP beneath and send
a message to server side and then the server would return the appropriate
file handle and so on, and other messages like ACCESS,READ which would
internally be translated as RPC;s to the server. How do I do that without
using XDR?
Would the set of file that contains these procedures be called NFS
Protocol only. I'm getting confused between the actual protocol and the
RPC that is used to implement it.Somehow, reading RFC's and other material
has got me very confused.
I need a clear approach so I can divide what I have to do step by step
into modules i.e what part of the NFS V3 Protocol specification can be
implemented and what can not be.
Thank you so much.