You must save your games if you want to re-open them again later.
When you first use Scratch on a computer, you should make a folder in which to save your games.
You should create a folder the first time you save a game.
Complete these steps ..
1. Go to "File > Save as" ..
2. Click on the new folder icon then click to name the new folder. Use your name (eg "Nathan Watts") ..
.. then click "OK".
3. Next, find your the folder you have created in the list ..
4. You must open your folder before saving your game. Double click or click the "OK" button to open your folder ..
5. Click in the "New filename" box and type a name for your game, then click the "OK" button ..
6. From now on, you can save your games in this folder. Just make sure you double click to open the folder before naming and saving your game.
To open a saved game, complete these steps ..
1. Go to File > Open ..
2. Find the folder that your game is saved in double-click it to open it ..
3. Click on the game you want to open and then click the "OK" button.