Thanks a lot!
For PC/Mac:
To update the game, you just download the latest version from here and unpack it into a new folder. You can delete the old version before or afterwards. As long as you're playing on the same PC/Mac, the save files will automatically be available in the new version of the game.
For Android:
Just download the newest .apk file onto your phone and install it by opening it. It should ask to update the game and then you can just follow the instructions.
Hope that helps! If not, let me know and I'll see what I can do. :)
Edit: Formatting