Update README.md

Author: PixelProphecy

README.md

@@ -1,2 +1,27 @@
 # gml_npp
-Syntax highlighting for GML (Game Maker Language) files in Notepad++
+## What it is
+A simple XML file to import as User Defined Language in Notepad++ which allows syntax highlighting of files written in GML (Game Maker Language).
+
+## Issues
+There might be some issues with folding of regions.
+
+## Installation
+
+1. Download the `gml_npp.xml` file
+2. Open Notepad++
+3. In the menu bar, click "Languages" and to the bottom, "Define your language..."
+4. Click "Import"
+5. Select and open the `gml_npp.xml` file you downloaded before
+6. Close the Language Definition Window.
+
+Each time you want to highlight GML  markup, just select it from the Language menu. It will be at the bottom with the other user defined styles.
+
+### Alternate Method
+(from the [Notepad++ website](http://notepad-plus.sourceforge.net/uk/site.htm))
+
+1. Download the user-defined language to your computer
+2. Open the file with your favourite text editor (such as Notepad++ or notepad)
+3. Click start, run, type (or paste in) `%APPDATA%\Notepad++` then click ok
+4. Open `userDefineLang.xml` with a text editor
+5. If this is the first userdefined language you are adding, copy/paste the entire first file (which you downloaded) into the userDefineLang.xml, replacing all that was there. If this is the second or more language you add, simply copy everything from the first file starting at `<UserLang...>` to `</UserLang>` and paste it at the end of the `userDefineLang.xml` right before `</NotepadPlus>`
+6. Save the newly improved `userDefineLang.xml`