= Step 1: Add a Source File to the Build System =

To begin adding a new plugin, create a new source file in the `litmus/` directory and add it to the build system.

 1. Create the empty file `litmus/sched_demo.c` (all file names are relative to the kernel repository).
    {{{
 $ touch litmus/sched_demo.c
    }}}
 2. Edit the file `litmus/Makefile` to add `sched_demo.o` to the list named `obj-y`.
 3. Compile the kernel to ensure that everything works.

After you've verified there are no errors, create commit with `git`.
{{{
$ git add litmus/Makefile
$ git add litmus/sched_demo.c
$ git commit
}}}

On to the [[../Step2|next step]].