Typing in full sentences may make it easier for us to understand what you are trying to say.
Next, try reading the help file in the scripting wizard.
Third, Use a subject title that adequately explains your problem.
Finally, to use the scripting wizard:
Go to the file menu and select "Read Project" and open your project.
Select the button you want to use to shoot (from the tab up top that says Button 1, etc)
Then choose the "Create Sprite Instance" radio button.
From the first dropdown list ("Instance Of") choose the name of the sprite you want to use as the bullet (or type it in if it's not in the list)
Select the inventory item you want to use as bullets (if you want to. You don't have to).
Select the audio clip you want to play when the bullet is shot from the gun (again, only if you want to)
Then fill in the maximum number of bullets you want to exist at any given time.
Then, choose the options you want the bullet to have. For example, choose "In direction of the player sprite" to make the bullet fire whatever direction the player is looking. And select probably at least one of the "Stop sprite when..." checkboxes
Then click "Write to file" and save the file in the same directory as your project (for easy finding).
Then, in SGDK, open the Player Settings and Inventory dialogue (The key button in the toolbar)
Click the button next to "Default Script" and select the script you just made.
Save the project.
Create a shortcut on the desktop (with the arrow inside a white box icon on the toolbar).
Use the shortcut on the desktop to test the game.
