So you're surfing along and you find a really cool script for your Gimp and you just HAVE to have it. You click the download button and a blank screen full of text and gobbelee gook pops up. "Now what?", you think. I have read and read posts and always got confused on how to save these. We are in the land of Word, Word Pad and Notepad. These may all be fruits but one is a fruit salad, one is a fruit cocktail and the other is just an apple. SCM files love apples.
If you can't click and download the file simply as an SCM and are forced to copy and paste code, then you need to open NOTEPAD. The other programs will not let you save in the format you need and sometimes Word will actually try to act on scripts typed on them, not just Gimp scripts, web scripts too. To avoid these bugs, stick to Notepad.
Ctrl-A to select all, click on blank page in Notepad, go to menu Edit>Paste.
File>Save As>"the name the people called the script including the .scm is so important here"
Before you hit Okay make sure you save as "all files". So if you are copying a glass script, it will be called "glass.scm".
Now go to the folder it was saved in and verify it saved as an SCM file (hovering or right clicking, properties will show you this info). If you are successful, you want to copy and paste this file into your .gimp>scripts folder - this is called "installing". Keep the original file in a folder to back up to disk when you back up your files (and I know you back them up the same day you change the batteries in your smoke detector).
Notes: you can save the whole page the script tut is on, but you will still need to save the script to a file and import it to Gimp. You might want to do this because the tut will walk you through neat tricks on using the script.
IMPORTANT: When installing scripts, it won't show up until you start Gimp. If you install it with Gimp already running, you will need to restart Gimp completely. It's not like brushes and patterns where you can just hit refresh.