made building.md suck less.

docs/building.md

@@ -1,9 +1,35 @@
 # Building PsychOS
-## Building
+## Building on \*nix systems
+### 1. Obtain source.
+
+```
+git clone https://github.com/XeonSquared/PsychOS.git
+```
+
+### 2. Build source.
+
 ```
 ./genkernel.sh
 ```
-Builds a kernel using files in `build.cfg` and saves it to `kernel.lua`
+
+`genkernel.sh` is a wrapper script for genkernel.lua which is a wrapper program for the genkernel module that is actually used to generate the code.
+
+To change the modules included, modify build.cfg.
+
+## Building on PsychOS
+### 1. Obtain source and relevant software.
+At present, the way to do this is "copy them onto the installation."
+
+If genkernel() isn't included in your kernel you can run it as a program using luash's ! prefix.
+
+### 2. Run genkernel()
+
+```
+genkernel("/boot/PsychOS/build.cfg","custom")
+```
+
+This will generate a kernel from the files listed in /boot/PsychOS/build.cfg with "custom" as part of the kernel name and return the resulting kernel as a string. You can then write that string to a file or similar.
+
 ## Files
 ### genkernel.sh
 genkernel.sh calls `genkernel.lua build.cfg`.