Add a note about the build process to README

README.md

@@ -11,16 +11,22 @@ https://stronghold.openkrosskod.org/~dmitmel/ccloader3/
 
 ## Building from source
 
-(This section may be moved in the future)
-
 ```bash
 cd /somewhere/but/preferably/inside/the/crosscode/directory
 git clone https://github.com/CCDirectLink/CCLoader3.git ccloader3
 cd ccloader3
 npm install
+mv runtime/src/extension-preloader.ts .
+npm run build
+mv extension-preloader.ts runtime/src
 npm run build
 ```
 
+Yes, that moving about of the extension-preloader is intentional and required. It is a bug in how
+TypeScript compiles files in alphabetical order, and the extension-preloader requires a file that
+has not been built yet according to the alphabetical order. This will be fixed once the module
+structure of the modloader is redone.
+
 Then edit the game's `package.json` and point the path in the `main` field to the location of the
 `main.html` page in the `ccloader3` directory.