Added build instructions

README.md

@@ -1,5 +1,39 @@
 # MultICE
 ## The MultIplexed Computing Environment for OpenComputers
+A simple, unprotected, cooperative multitasking operating system.
+
+### Building
+MultICE uses a relatively simple build system. It has been tested on Arch Linux, Debian Linux, OpenOS and Plan9k.
+#### 1. Choose modules.
+The system is made out of modules from the `modules/` directory. When you run the build script, it assembles them, and optionally optomises the code for space.
+
+Modules are specified in the `modules.cfg` file and are relative to the `modules/` folder.  
+An example for interactive usage with networking:
+```
+base/header.lua
+drivers/dterm.lua
+library/print.lua
+drivers/keyboard.lua
+library/net.lua
+applications/luash.lua
+base/footer.lua
+```
+#### 2. Configure build system
+The build system has a configuration file `build.cfg`.
+##### `optomise`
+Can either be yes or no.  
+Specifies whether to run the simple optomisation function on the kernel.
+##### `test`
+Can either be yes or no.  
+Specifies whether to test the final kernel (using load). Only picks up syntax errors.
+##### `log`
+Can either be yes or no.  
+Specifies whether to output log files.
+##### `opath`
+Specifies where to put the output kernel.
+
+#### 3. Build.
+Simply run `build.lua`. Under OpenOS or plan9k that may just be going to the right dir and entering `build`, but under proper UNIX systems it may involve `lua build.lua`.
 
 ### Base OS API
 #### s(name,function,environment)