Installation instructions for Windows (XP, vista or 7):
- Press Win+R to open the "Run" menu
- Type in %appdata% and hit Enter
- Now you should be in your appdata folder
- Open the folder called "Minecraft"
- Now open "bin"
- replace the (existing) minecraft.jar with the one you just downloaded and voilĂ , you can now play 1.9 pre-release!