This lesson will guide you on how you can edit a script using the Script Editor that is part of the Scripts toolbar. Unfortunately, some features seem to either no longer be available, or they are "broken", but I will explain them in the video.
If the video above is causing issues, here is a copy on YouTube: https://youtu.be/er13D2y-u0A (please do not share)
Play around with editing your script. Record other scripts, using different size images, different shapes for the selection, different settings for the Drop shadow. You can even try to apply other simple effects, like a texture, or a bevel.
See all those commands in the Script Editor, and see what they look like when you choose the Text editor instead.
For your homework, tell us what you did. If you want to share a screenshot, that is great (remember to resize the image to a maximum of 600 pixels). What did you observe? Do you have questions about that lesson?
The forum thread is here.
If you want to download Notepadd++, you can do so here. It is totally free.