chore: update README.md

README.md

@@ -1,10 +1,21 @@
 # H3-Scaleform-Decompilation-Project
 
-## Known Issues
-* Fonts look weird in some places.
-* Font colour is not correct for distance text in-game and probably other things as well.
-* Some buttons in the main menu like the "Go Online" and "Patch Notes" have a broken icon.
-* Game version text is too small.
+## Building
+### Prerequisites
+You will need the following things:
+* Flex SDK - https://flex.apache.org/download-binaries.html (apache-flex-sdk-4.16.1-bin.zip).
+* Air SDK - https://airsdk.harman.com/download (AIR SDK for Flex Developers).
+* IntelliJ IDEA with the Flash/Flex plugin (has to be the ultimate edition).
+  * You could use an alternative free IDE like FlashDevelop, but you'd have to set it up manually.
+
+### Steps
+1. Extract Flex SDK into `C:\FlexSDK` (or a similar location).
+2. Extract the contents of Air SDK into the `C:\FlexSDK` folder.
+3. Open up this project in IDEA.
+4. Point IDEA to the Flex SDK:
+
+   File -> Project Structure -> SDKs -> Click the + icon -> Add new Flex/AIR SDK... -> Point it to `C:\FlexSDK` or whichever folder you choose earlier.
+5. Hit Ctrl - F9 and it should build all the SWFs.
 
 ## Todo
 * Organise all the symbols in the fla files.