To change your start and end G-code scripts, you’ll have to use your slicer (in this case; Cura)

1. Open Cura and navigate to your machine settings by clicking the “Preferences” tab.
2. After opening up the Preferences menu, click “Printer”, and then click on the printer you're setting up.
3. Click “Machine Settings”, and you’ll see the start and end G-code scripts in the two boxes on the bottom of the pop-up screen.
4. Click “Machine Settings”, and you’ll see the start and end G-code scripts in the two boxes on the bottom of the pop-up screen.
5. Edit these G-code scrips to whatever you like by copy-pasting existing scripts or writing your own.
6. Once you’re done editing your scripts, click out of the text box to save your new start and end G-code scripts.