1) First make sure that you have installed Notepad++.
2) Download this pack
3) Extract this pack
4) Copy Galaxy.xml to "...\Notepad++\plugins\APIs\"
5) Copy JassCraft.xml to "...\Notepad++\themes\"
6) Run Notepad++
7) Click "User-Defined Dialogue" button/icon
8) In appearing dialog click on "Import" and select GalaxyLang.xml, close the dialog
9) Go to Settings->Preferences->Backup/Auto-completition and set settings to this ones
10) Go to Settings->Style Configurator and select JassCraft theme.
11) Restart Notepad++
12) Go to Language->Galaxy
13) Start coding and enjoy!
* Note that when you are saving your code make sure to use extension .galaxy
* Note that Notepad++ has limit of 3*10^4 chars for each section (consts, funcs, types and keywords)
Galaxy language has too much natives so notepad++ does not highlight a few of them