Try with starting some Learn C tutorial
or some video tutorial
If you really want to learn coding that read How to Start the Homework or a Developer Career?
in which I condensed my experiences in software development and IT. You need to get a team player and write "clean code" so your mates can understand them.
Developing an OS is way to much for a person, so you better start with some application.
some tips: use functions and structs with understandable names and install some IDE like Visual Studio..