The easiest way to save data is to store them in global variables, but it's better if your game has is own directory (to avoid creating lots of variable in the "main" folder); you'll just have to read you variables when needed to load a game.
You can also push all your variables in a "data" file (see manual for help about "data" functions, like "NewData"), it's slower but you'll have only one file per savegame, instead of lots of small ones.
